We can strength-reduce JSResolvePromise(p,v) to JSFulfillPromise(p,v)
if the v is known to be a primitive. This not only avoids the dynamic
checks for v inside JSResolvePromise, but also removes the need to
have a frame state, as the JSFulfillPromise operation cannot call
back into arbitrary JavaScript, and thus cannot deoptimize lazily.

This triggers for example for async functions where the return value
is known (to TurboFan) to be a primitive value.

Bug: v8:7253
Change-Id: I4698d6026e0632ab3e2fef6c7f4aaacf6c2a508c
Reviewed-on: https://chromium-review.googlesource.com/c/1288449
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56758}