When |ResolvePromise| is resolved with a promise that is
already fulfilled or resolved, we can short circuit the
promise resolution procedure by directly looking up the
result from the promise. We save creating two closures, enqueuing in
the promise queue, and running through PromiseThen.

This patch uses IsPromise to check if the |resolution| object is a native
promise and also checks if |resolution.then| hasn't been monkey
patched.

This patch adds some redundant code from PromiseThen like setting
the promiseHasHandlerSymbol and calling PromiseRevokeReject call,
which would've been taken care of by PromiseThen in the old code path.

This patch results in a 13.8% improvement(over 5 runs) in the bluebird
benchmarks.

BUG=v8:5046

Review-Url: https://codereview.chromium.org/2028253004
Cr-Commit-Position: refs/heads/master@{#36765}