Concurrent sparkplug adds functions to batches and sends those batches
off for compilation, but doesn't note what functions are currently
compiling. This means that we can spawn multiple compilation jobs for a
function, most of which will be throw away.

Add a bit to SharedFunctionInfo to note whether concurrent compilation
has been started for it.

Change-Id: Ifa442481611044713b2893488387e97f071e408a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3702336
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81116}