EXPIRE precision test more attempts and more tolerant (#12150)

The test failed on MacOS:
```
*** [err]: EXPIRE precision is now the millisecond in tests/unit/expire.tcl
Expected 'somevalue {}' to equal or match '{} {}'
```

`set a [r get x]`, even though we tried 10 times, sometimes we
still get {}, this is a time-sensitive test.

In this PR, we add the following changes:
1. More attempts, change it from 10 to 30.
2. More tolerant, change the `after 900` to `after 800`.

In addition, we judging $a in advance and changing `after 1100`
to `after 300`, this will save us some times.

1 files changed, 8 insertions, 6 deletions

diff --git a/tests/unit/expire.tcl b/tests/unit/expire.tcl
index 5ee4488b3..ec9d73cc2 100644
--- a/tests/unit/expire.tcl
+++ b/tests/unit/expire.tcl
@@ -76,20 +76,22 @@ start_server {tags {"expire"}} {
         # This test is very likely to do a false positive if the
         # server is under pressure, so if it does not work give it a few more
         # chances.
-        for {set j 0} {$j < 10} {incr j} {
+        for {set j 0} {$j < 30} {incr j} {
             r del x
             r setex x 1 somevalue
-            after 900
+            after 800
             set a [r get x]
-            after 1100
+            if {$a ne {somevalue}} continue
+            after 300
             set b [r get x]
-            if {$a eq {somevalue} && $b eq {}} break
+            if {$b eq {}} break
         }
         if {$::verbose} {
             puts "millisecond expire test attempts: $j"
         }
-        list $a $b
-    } {somevalue {}}
+        assert_equal $a {somevalue}
+        assert_equal $b {}
+    }
 
     test "PSETEX can set sub-second expires" {
         # This test is very likely to do a false positive if the server is