Move the CompileWithBaseline interface to the Compiler class, as
CompileBaseline, which will do the additional work of pre-compiling
to bytecode, ensuring there is a feedback vector, and setting the
code on the function closure.

As a drive-by, fix v8_enable_trace_unoptimized to have a blank default
value, so that v8_enable_trace_ignition/v8_enable_trace_baseline_exec
can set it.

Bug: v8:11420, v8:11429
Change-Id: If715161de71f7d9300f3fdcbb50cc678b1fcdfdf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2697352Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72819}