This CL locally improves Number.toString by 5% for the slow case where
the number is not found in the cache.

- Introduce NumberCacheMode to avoid needless querying of the cache
- Allow for some more inlining

Bug: v8:10477
Change-Id: I4163e85db587ab3a6e89c126f81f6095fdb02b2a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2172793Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67768}