[analyzer][NFC] Fix unused variable warning

Author: frasercrmck

clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp

@@ -43,8 +43,7 @@ tryToFindPtrOrigin(const Expr *E, bool StopAtFirstRefCountedObj) {
     if (auto *call = dyn_cast<CallExpr>(E)) {
       if (auto *memberCall = dyn_cast<CXXMemberCallExpr>(call)) {
         if (auto *decl = memberCall->getMethodDecl()) {
-          std::optional<bool> IsGetterOfRefCt =
-              isGetterOfRefCounted(memberCall->getMethodDecl());
+          std::optional<bool> IsGetterOfRefCt = isGetterOfRefCounted(decl);
           if (IsGetterOfRefCt && *IsGetterOfRefCt) {
             E = memberCall->getImplicitObjectArgument();
             if (StopAtFirstRefCountedObj) {