Fix compiler-rt test

Author: Sirraide

compiler-rt/test/hwasan/TestCases/libc_thread_freeres.c

@@ -1,4 +1,4 @@
-// RUN: %clang_hwasan -Wno-error=return-type %s -o %t && %env_hwasan_opts=random_tags=1 %run %t
+// RUN: %clang_hwasan %s -o %t && %env_hwasan_opts=random_tags=1 %run %t
 
 #include <pthread.h>
 #include <sanitizer/hwasan_interface.h>
@@ -11,6 +11,7 @@ void *ThreadFn(void *) {
   __hwasan_enable_allocator_tagging();
   // This will trigger memory deallocation in __strerror_thread_freeres,
   // at a point when HwasanThread is already gone.
+  return NULL;
 }
 
 int main() {