The call to EnsureSourcePositionsAvailable for a given SharedFunctionInfo
is now done in the serializer for each SFI that is marked as serialized for
compilation. This will enable brokerization of the JSInliner class.

Change-Id: I7821a50fcac8a3e19386e98758f2b0dea3023bb6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1582400
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61260}