[asan][test] Fix flake in asan_lsan_deadlock test

While the current test checks that a deadlock doesn't occur, it also
assumes that lsan reporting happens at the end of the program as part of
the summary. However, it sometimes happens that due to ordering the
stack-buffer-overflow is reported differently. In these cases the error
message will be prefixed with 'ERROR:' instead of 'SUMMARY:'. Since the
verbiage of the reporting isn't the point of the test, we can relax the
check slightly to avoid test flake due to non-determinism in the
execution ordering of the program. Fixes #140646.

Author: ilovepi

compiler-rt/test/asan/TestCases/asan_lsan_deadlock.cpp

@@ -55,7 +55,7 @@ int main(int argc, char **argv) {
      * 1. ASan's thread registry lock (B) during the reporting 
      * 2. dl_iterate_phdr lock (A) during symbolization
      */
-    // CHECK: SUMMARY: AddressSanitizer: stack-buffer-overflow
+    // CHECK: AddressSanitizer: stack-buffer-overflow
     arr[argc] = 1; // Deliberate OOB access
   });