[Sanitizers] Fix decorator test to ignore the executable attribute as this was causing flakiness.

[vitalybuka]

Is this after callback patch? I don't remember I've seen this before

[browneee]

I just wrote the same patch, plus this comment:

In the regex below, the x permission is matched with a '.'.
We would like '-', but sometimes 'x' is set, causing buildbot flakiness.
This might be due to READ_IMPLIES_EXEC being set (when it occurs all regions with r also have x).
TODO: investigate further and change 'rw{{[-x]}}p' back to 'rw-p'

[browneee]

Suggest adding a comment and submitting to make that buildbot green.

Can revert later when we figure out why.

[kstoimenov]

Added a commented recommended by browneee@.

[vitalybuka]

Why do you think it's flakiness, it's consistently red on two different host

[kstoimenov]

Updated the comment.

[vitalybuka]

And it's consistently red after D114558.

[kstoimenov]

Thanks, Andrew. I will submit my patch. I've added your comments.

compiler-rt/test/sanitizer_common/TestCases/Linux/decorate_proc_maps.cpp

 int main(void) {
   pthread_t t;
   void *res;
   pthread_create(&t, 0, ThreadFn, 0);
   pthread_join(t, &res);
   return (int)(size_t)res;
 }
 
-// CHECK-asan: rw-p {{.*}} [low shadow]
+// In the regex below, the exec permission is matched for both '-' and 'x'.
+// We would like '-', but sometimes 'x' is set, causing buildbot flakiness.
+// This might be due to READ_IMPLIES_EXEC being set (when it occurs all
+// regions with r also have x).
+// TODO: investigate further and change 'rw{{[-x]}}p' back to 'rw-p'
+
+// CHECK-asan: rw{{[-r]}}p {{.*}} [low shadow]
 // CHECK-asan: ---p {{.*}} [shadow gap]
-// CHECK-asan: rw-p {{.*}} [high shadow]
+// CHECK-asan: rw{{[-r]}}p {{.*}} [high shadow]
 
 // CHECK-msan: ---p {{.*}} [invalid]
-// CHECK-msan: rw-p {{.*}} [shadow{{.*}}]
+// CHECK-msan: rw{{[-r]}}p {{.*}} [shadow{{.*}}]
 // CHECK-msan: ---p {{.*}} [origin{{.*}}]
 
-// CHECK-tsan: rw-p {{.*}} [shadow]
-// CHECK-tsan: rw-p {{.*}} [meta shadow]
+// CHECK-tsan: rw{{[-r]}}p {{.*}} [shadow]
+// CHECK-tsan: rw{{[-r]}}p {{.*}} [meta shadow]
 
 // Nothing interesting with standalone LSan and UBSan.
 // CHECK-lsan: decorate_proc_maps
 // CHECK-ubsan: decorate_proc_maps