[wasm] Use auto* for memory_tracker pointer

Change-Id: I453c356a6d9098739e7bf32d3c7a75c8afb7cab2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1554106Reviewed-by: Ben Smith <binji@chromium.org>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60642}

src/wasm/wasm-objects.cc

@@ -1255,7 +1255,7 @@ int32_t WasmMemoryObject::Grow(Isolate* isolate,
                                uint32_t pages) {
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm"), "GrowMemory");
   Handle<JSArrayBuffer> old_buffer(memory_object->array_buffer(), isolate);
-  auto memory_tracker = isolate->wasm_engine()->memory_tracker();
+  auto* memory_tracker = isolate->wasm_engine()->memory_tracker();
   if (!memory_tracker->IsWasmMemoryGrowable(old_buffer)) return -1;
 
   // Checks for maximum memory size, compute new size.