This reverts commit 69c4010c1b3d43e2e179421e27379aaa5aeeb6d8.

The failure is actually caused by the fact that default alignment of
stack on x86 is 4 bytes.
So, another solution should be proposed to fix the issue for other
compilers (and, potentially, other targets).  E.g. do not place
AO_double_t volatile variables on stack.

Passing an unaligned AO_double_t pointer to AO double-wide primitives
results in an undefined behavior of the latter when running on x86 (or
violation of the corresponding assertion on the alignment).
MS VC++/x86 aligns AO_double_t values on a 4-byte boundary by default.
For the proper alignment, __declspec(align(8)) should be applied to
variables defined in the client code (which uses double-wide AO
primitives).  Unfortunately, the attribute cannot be added to
AO_double_t definition itself because the compiler does not allow the
attribute for function arguments.

This patch introduces AO_DOUBLE_ALIGN attribute for use by clients of
the double-wide AO primitives (and, thus, AO_stack clients).
Matters only Visual Studio compiler for X86.
The inner clients (atomic_ops_malloc, test_atomic, test_stack) are
updated to use this attribute.

* doc/README_win32.txt [x86] (AO_DOUBLE_ALIGN): Document.
* src/atomic_ops/sysdeps/generic_pthread.h (AO_DOUBLE_ALIGN): Define
(as empty).
* src/atomic_ops/sysdeps/standard_ao_double_t.h [!_WIN64 && _WIN32
&& !__GNUC__ && _MSC_VER] (AO_DOUBLE_ALIGN): Define as declspec
align(8); document it.
* src/atomic_ops/sysdeps/standard_ao_double_t.h [!AO_DOUBLE_ALIGN]
(AO_DOUBLE_ALIGN): Define as empty (otherwise).
* src/atomic_ops_stack.h [AO_USE_ALMOST_LOCK_FREE && !AO_DOUBLE_ALIGN]
(AO_DOUBLE_ALIGN): Likewise.
* src/atomic_ops_malloc.c (AO_free_list): Use AO_DOUBLE_ALIGN attribute.
* tests/test_stack.c (the_list): Likewise.
* src/atomic_ops_stack.h [!AO_USE_ALMOST_LOCK_FREE] (AO_stack_t):
Document AO_DOUBLE_ALIGN usage (by clients).
* tests/test_atomic_include.template (test_atomicXX): Use
AO_DOUBLE_ALIGN attribute for old_w and w double-wide local variables
(to avoid alignment assertion violation or AO primitives undefined
behavior on x86 if the test code is compiled by VC++).

* tests/test_malloc.c (print_list): Define only if DEBUG_RUN_ONE_TEST.
* tests/test_stack.c (print_list): Define only if VERBOSE.

Long (32-bit) type is sufficient to represent time delta (duration)
in test_stack.

* tests/test_stack.c (get_msecs): Change return type from long long
to unsigned long (use lowest 32 bits of time value).
* tests/test_stack.c (main): Change type of start_time local variable
to unsigned long; remove redundant type cast.

* tests/test_stack.c [VERBOSE] (main): Print value name along with the
value itself; print "ms" for time value; remove extra get_msecs() call.

* tests/test_stack.c (run_one_test): Define "j" local variable only
if VERBOSE.
* tests/test_stack.c (main): Do not define "sum" local variable (and
don not compute the sum) if NO_TIMES.

* src/atomic_ops_malloc.c (abort): Define to _exit(-1) if _WIN32_WCE
or __MINGW32CE__ (since there is no abort() in WinCE).
* tests/run_parallel.h (abort): Likewise.
* tests/test_stack.c (abort): Likewise.

* tests/test_stack.c (main): Add debug printing of exper_n, nthreads,
max_nthreads and list_length before add_elements call (if VERBOSE).

* tests/test_stack.c (main): Cast "code" argument of fprintf calls to
unsigned int to match printf format specifier.

* tests/test_stack.c (run_one_test): Change type of "index" local
variable from long to int to match printf format specifier (when
VERBOSE defined); cast from "arg" pointer to integer via size_t (to
avoid 64-bit compiler warning).