The functionality is unused and we are simplifying OptimizationMarker
usage.

Drive-by: Remove unused return value of Compiler::CompileOptimized.
Drive-by: Don't add kStackSpaceRequiredForCompilation as gap to the
stack check when compiling concurrently, i.e. on another thread.

Bug: chromium:757467
Change-Id: Ibbe204b82bf937b9eb74f9eb2c3fd2d719d53ef9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3416245Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78800}