Moves TurboProp to optimize around the time of TurboFan right now, and
removes some of the special-case logic we had to avoid aggressive
early optimization of TurboProp.

BUG=v8:9684

Change-Id: I0299408891ff6fd57e6523ff309b5f16624466a9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2964814
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75163}