bionic tests: use GTEST_SKIP.

Also be a bit more to the point in our messages, focusing on "why" not
"what".

Test: ran tests
Change-Id: I297806c7a102bd52602dcd2fcf7a2cd34aba3a11
diff --git a/tests/utils.h b/tests/utils.h
index cc1aa8c..fe41019 100644
--- a/tests/utils.h
+++ b/tests/utils.h
@@ -64,7 +64,7 @@
   return &__hwasan_init != 0;
 }
 
-#define SKIP_WITH_HWASAN if (running_with_hwasan()) { return; }
+#define SKIP_WITH_HWASAN if (running_with_hwasan()) GTEST_SKIP()
 
 static inline void* untag_address(void* addr) {
 #if defined(__LP64__)