Move V8PerIsolateData initialization before calling AddMessageListener

If chrome is started with --js-flags=--prof, AddMessageListener will call
Logger::LogCodeObjects that fetchs the uninitialized V8PerIsolateData for blink.

Moving the initialization before AddMessageListener seems to fix it.

BUG=340521

Review URL: https://codereview.chromium.org/131483012

git-svn-id: svn://svn.chromium.org/blink/trunk@166467 bbb929c8-8fbe-4397-9dbb-9b2b20218538