During background compilation, we check
SharedFunctionInfo::HasBreakInfo() to see if the function has
breakpoints for debugging, generally deciding not to inline the
function if so. We were concerned about the status of this bit
changing on the main thread. Happily, the main thread deoptimizes
all functions that inline the given function, and shuts down all
background compilation jobs as well. So it is not a meaningful
concern (that of say, ignored breakpoints). Updated a comment to
record this finding.

Bug: v8:7790
Change-Id: I7adbc5d19fc45eb7f4df1400c33f5988d9dac58d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2848409
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74183}