Calls to Flip and ResetLinearAllocationArea of SemiSpaceNewSpace are
(almost) always called together, and always at the start of evacuation.
Introducing NewSpace::EvacuatePrologue, allows removing these methods
from SemiSpaceNewSpace public interface and reduces future branches
between the semi space and paged new space cases.

Bug: v8:12612
Change-Id: Ic589a48c1e7751631603da757f4f5f7edb69e571
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3650599Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80561}