Adopt to new MicrotasksCompletedCallback signature

V8 updated the signature of MicrotasksCompletedCallback to take a void
pointer user data, and is deprecating the old signature.
This CL updates its user to use the new one.

Change-Id: I24990f68b2964fa80554689947746636958f59cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1504660Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638471}

third_party/blink/renderer/platform/bindings/v8_per_isolate_data.cc

@@ -67,7 +67,7 @@ static void BeforeCallEnteredCallback(v8::Isolate* isolate) {
   CHECK(!ScriptForbiddenScope::IsScriptForbidden());
 }
 
-static void MicrotasksCompletedCallback(v8::Isolate* isolate) {
+static void MicrotasksCompletedCallback(v8::Isolate* isolate, void*) {
   V8PerIsolateData::From(isolate)->RunEndOfScopeTasks();
 }