Leak full Wparentheses suppression for GCC 9

Reported as an issue on Discord. I thought that by GCC 9, the
C++ frontend was fixed enough to support `_Pragma`-based
suppression correctly, but apparently I was wrong.

src/catch2/internal/catch_test_macro_impl.hpp

@@ -14,9 +14,9 @@
 #include <catch2/internal/catch_stringref.hpp>
 #include <catch2/internal/catch_source_line_info.hpp>
 
-// We need this suppression to leak, because it took until GCC 9
+// We need this suppression to leak, because it took until GCC 10
 // for the front end to handle local suppression via _Pragma properly
-#if defined(__GNUC__) && !defined(__clang__) && !defined(__ICC) && __GNUC__ < 9
+#if defined(__GNUC__) && !defined(__clang__) && !defined(__ICC) && __GNUC__ <= 9
   #pragma GCC diagnostic ignored "-Wparentheses"
 #endif