[cleanup] Fix -Wshadow warnings

Bug: v8:12244,v8:12245
Change-Id: I816930bfc65a2e597a41562cb115af5d0bca199b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3296147Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78047}

test/cctest/heap/test-shared-heap.cc

@@ -168,7 +168,7 @@ void AllocateInSharedHeap(Isolate* shared_isolate, int iterations = 100) {
   SetupClientIsolateAndRunCallback(
       shared_isolate,
       [iterations](v8::Isolate* client_isolate, Isolate* i_client_isolate) {
-        HandleScope scope(i_client_isolate);
+        HandleScope outer_scope(i_client_isolate);
         std::vector<Handle<FixedArray>> arrays;
         const int kKeptAliveArrays = 1000;