The SerializerForBackgroundCompilation needs bytecode analysis for loop
target analysis, but doesn't require the much more expensive liveness
analysis. In order to move more work off the main thread, perform fast
bytecode analysis without liveness analysis in
SerializerForBackgroundCompilation, and then move the full bytecode
analysis to the background thread in BytecodeGraphBuilder.

BUG=v8:7790,v8:9684

Change-Id: I63ef80ecab8ad0c56953c72be31abc8f5a74b9c1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2593329Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71767}