Don't use deprecated V8 HeapProfiler API

This change fixes the following warning:
tests\ListenerLeakTest.cpp(62): warning C4996: 'v8::HeapProfiler::TakeSnapshot': was declared deprecated

BUG=None

Review URL: https://codereview.chromium.org/14251007

git-svn-id: svn://svn.chromium.org/blink/trunk@148376 bbb929c8-8fbe-4397-9dbb-9b2b20218538