Suppress uncounted local var warning in RETURN_IF_EXCEPTION

https://bugs.webkit.org/show_bug.cgi?id=273697

Reviewed by Ryosuke Niwa.

Add a macro to supress warning on the vm variable not being counted when
the preprocessor expands the RETURN_IF_EXCEPTION macro in a function
body.

This patch removes more than 2000 warnings when checking all the webkit
codebase.

* Source/JavaScriptCore/runtime/ExceptionScope.h:

Canonical link: https://commits.webkit.org/278560@main

Source/JavaScriptCore/runtime/ExceptionScope.h

@@ -108,7 +108,7 @@ class ExceptionScope {
 #endif // ENABLE(EXCEPTION_SCOPE_VERIFICATION)
 
 #define RETURN_IF_EXCEPTION(scope__, value__) do { \
-        JSC::VM& vm = (scope__).vm(); \
+        SUPPRESS_UNCOUNTED_LOCAL JSC::VM& vm = (scope__).vm(); \
         EXCEPTION_ASSERT(!!(scope__).exception() == vm.traps().needHandling(JSC::VMTraps::NeedExceptionHandling)); \
         if (UNLIKELY(vm.traps().maybeNeedHandling())) { \
             if (vm.hasExceptionsAfterHandlingTraps()) \