DevTools: Dump function location when printing it in console and support inspect() for functions.

BUG=279442
R=pfeldman

Review URL: https://chromiumcodereview.appspot.com/23692002

git-svn-id: svn://svn.chromium.org/blink/trunk@156923 bbb929c8-8fbe-4397-9dbb-9b2b20218538