V8ScriptRunner should accept v8::Value as an receiver

Since the primitive value can be used as an receiver of a function call
from ECMA262 5th, V8ScriptRunner should accept v8::Value as an receiver.

This change should be landed after the V8-side CL[1] is landed and V8 is
rolled.

[1]: https://chromiumcodereview.appspot.com/24920003/

BUG=

Review URL: https://codereview.chromium.org/25313003

git-svn-id: svn://svn.chromium.org/blink/trunk@158583 bbb929c8-8fbe-4397-9dbb-9b2b20218538