There are very few cases where OSR code can be re-used, and where the
function won't be non-concurrently optimized after OSR has happened.
Maintaining the OSR code cache is unnecessary complexity, and caching
OSR prevents us from e.g. seeding the optimizer with the actual OSR
values.

So, this patch removes it.

Change-Id: Ib9223de590f35ffc1dc2ab593b7cc9fe97dde4a6
Reviewed-on: https://chromium-review.googlesource.com/552637
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46306}