This ensures that breaking on inlined builtins works, even when
compiling concurrently. This CL also introduces the member
Isolate::AbortConcurrentOptimization.

R=sigurds@chromium.org

Bug: v8:178
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Ie6cbb48ebde18036888af2dd715862e7a14ddf9d
Reviewed-on: https://chromium-review.googlesource.com/912468
Commit-Queue: Yang Guo <yangguo@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51384}