[GWP-ASan] Fix 6413872

Use testing not zxtest in non-Fuchsia case

GitOrigin-RevId: df87e62cbd4b5090b5349247d29457706d2ac4e8
diff --git a/tests/harness.h b/tests/harness.h
index e6be68c..efac826 100644
--- a/tests/harness.h
+++ b/tests/harness.h
@@ -18,7 +18,7 @@
 #else
 #include "gtest/gtest.h"
 using Test = ::testing::Test;
-template <typename T> using TestWithParam = ::zxtest::TestWithParam<T>;
+template <typename T> using TestWithParam = ::testing::TestWithParam<T>;
 #endif
 
 #include "gwp_asan/guarded_pool_allocator.h"