1) Merge |AddBaselineCompilationUnits| into
   |InitializeRecompilationProgress|.
2) Rename |InitializeRecompilationProgress| to
   |InitializeRecompilation|.
3) Unify the update of |ReachedRecompilationTierField| in
   |compilation_progress_|.

R=ahaas@chromium.org
CC=duongn@microsoft.com

Bug: v8:9654
Change-Id: I58324b553bf226cacb355e387c235841fdea82d4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2071863
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66454}