Fix test errors for PYPY.

It looks like PYPY implementation has some issues with strings (or maybe
it's a subprocess bug?). Anyway, this is the full output:

PYTHONWARNINGS=all PSUTIL_TESTING=1 PSUTIL_DEBUG=1 pypy3 -c "import psutil.tests.runner as r; r.run(last_failed=True)"
psutil.tests.test_unicode.TestFSAPIsWithInvalidPath.test_proc_cmdline ... /home/giampaolo/svn/psutil/@psutil-test-30050f��: error while loading shared libraries: libpypy3-c.so: cannot open shared object file: No such file or directory
FAIL
psutil.tests.test_unicode.TestFSAPIsWithInvalidPath.test_proc_exe ... /home/giampaolo/svn/psutil/@psutil-test-30050f��: error while loading shared libraries: libpypy3-c.so: cannot open shared object file: No such file or directory
FAIL
psutil.tests.test_unicode.TestFSAPIsWithInvalidPath.test_proc_name ... /home/giampaolo/svn/psutil/@psutil-test-30050f��: error while loading shared libraries: libpypy3-c.so: cannot open shared object file: No such file or directory
FAIL
psutil.tests.test_process.TestProcess.test_long_cmdline ... /home/giampaolo/svn/psutil/@psutil-test-30050: error while loading shared libraries: libpypy3-c.so: cannot open shared object file: No such file or directory
FAIL
psutil.tests.test_process.TestProcess.test_long_name ... /home/giampaolo/svn/psutil/@psutil-test-3005001234567890123456789: error while loading shared libraries: libpypy3-c.so: cannot open shared object file: No such file or directory
FAIL
psutil.tests.test_process.TestProcess.test_prog_w_funky_name ... /home/giampaolo/svn/psutil/@psutil-test-30050foo bar ): error while loading shared libraries: libpypy3-c.so: cannot open shared object file: No such file or directory
FAIL

======================================================================
FAIL: psutil.tests.test_unicode.TestFSAPIsWithInvalidPath.test_proc_cmdline
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/giampaolo/svn/psutil/psutil/tests/test_unicode.py", line 184, in test_proc_cmdline
    self.assertEqual(cmdline, [self.funky_name])
AssertionError: Lists differ: [] != ['/home/giampaolo/svn/psutil/@psutil-test-30050f\udcc0\udc80']

Second list contains 1 additional elements.
First extra element 0:
'/home/giampaolo/svn/psutil/@psutil-test-30050f\udcc0\udc80'

- []
+ ['/home/giampaolo/svn/psutil/@psutil-test-30050f\udcc0\udc80']

======================================================================
FAIL: psutil.tests.test_unicode.TestFSAPIsWithInvalidPath.test_proc_exe
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/giampaolo/svn/psutil/psutil/tests/test_unicode.py", line 168, in test_proc_exe
    os.path.normcase(self.funky_name))
AssertionError: '' != '/home/giampaolo/svn/psutil/@psutil-test-30050f\udcc0\udc80'
+ /home/giampaolo/svn/psutil/@psutil-test-30050f\udcc0\udc80

======================================================================
FAIL: psutil.tests.test_unicode.TestFSAPIsWithInvalidPath.test_proc_name
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/giampaolo/svn/psutil/psutil/tests/test_unicode.py", line 175, in test_proc_name
    self.assertEqual(name, os.path.basename(self.funky_name))
AssertionError: '@psutil-test-30' != '@psutil-test-30050f\udcc0\udc80'
- @psutil-test-30
+ @psutil-test-30050f\udcc0\udc80
?                ++++++

======================================================================
FAIL: psutil.tests.test_process.TestProcess.test_long_cmdline
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/giampaolo/svn/psutil/psutil/tests/test_process.py", line 736, in test_long_cmdline
    self.assertEqual(p.cmdline(), cmdline)
AssertionError: Lists differ: [] != ['/home/giampaolo/svn/psutil/@psutil-test-[282 chars]789']

Second list contains 21 additional elements.
First extra element 0:
'/home/giampaolo/svn/psutil/@psutil-test-30050'

- []
+ ['/home/giampaolo/svn/psutil/@psutil-test-30050',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789',
+  '0123456789']

======================================================================
FAIL: psutil.tests.test_process.TestProcess.test_long_name
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/giampaolo/svn/psutil/psutil/tests/test_process.py", line 750, in test_long_name
    self.assertEqual(p.name(), os.path.basename(long_name))
AssertionError: '@psutil-test-30' != '@psutil-test-3005001234567890123456789'
- @psutil-test-30
+ @psutil-test-3005001234567890123456789

======================================================================
FAIL: psutil.tests.test_process.TestProcess.test_prog_w_funky_name
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/giampaolo/svn/psutil/psutil/tests/test_process.py", line 780, in test_prog_w_funky_name
    self.assertEqual(p.cmdline(), cmdline)
AssertionError: Lists differ: [] != ['/home/giampaolo/svn/psutil/@psutil-test-[102 chars], '']

Second list contains 7 additional elements.
First extra element 0:
'/home/giampaolo/svn/psutil/@psutil-test-30050foo bar )'

- []
+ ['/home/giampaolo/svn/psutil/@psutil-test-30050foo bar )',
+  '-c',
+  'import time; [time.sleep(0.01) for x in range(3000)];arg1',
+  'arg2',
+  '',
+  'arg3',
+  '']

----------------------------------------------------------------------

1 files changed, 1 insertions, 0 deletions

diff --git a/psutil/tests/test_unicode.py b/psutil/tests/test_unicode.py
index 91395ebf..eecd7dc4 100644
--- a/psutil/tests/test_unicode.py
+++ b/psutil/tests/test_unicode.py
@@ -298,6 +298,7 @@ class TestFSAPIs(_BaseFSAPIsTests, unittest.TestCase):
 
 @unittest.skipIf(PYPY and TRAVIS, "unreliable on PYPY + TRAVIS")
 @unittest.skipIf(MACOS and TRAVIS, "unreliable on TRAVIS")  # TODO
+@unittest.skipIf(PYPY, "unreliable on PYPY")
 @unittest.skipIf(not subprocess_supports_unicode(INVALID_NAME),
                  "subprocess can't deal with invalid unicode")
 class TestFSAPIsWithInvalidPath(_BaseFSAPIsTests, unittest.TestCase):