[Telemetry]: Don't fail in v8_object_stats if window.gc() is redefined by web page.

Some web pages re-define window.gc to something other than the exposed gc function.  This CL adds a try/catch to ensure we don't fail in this instance.

BUG=None

Review URL: https://codereview.chromium.org/113863003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241553 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241553