Since we use a ScopedPtrList to track cover grammar expressions we don't know
the position of the commas anymore. The position of the commas was used to
demark the initializer, which is needed to figure out whether we need hole
checks for variable references. (Typically only references within the
initializer need hole checks for the initialized variable.) Since we didn't
have the comma position, we simply used the position of the first expression as
the position of any subsequent comma, which would make it seem as if the
initializer body wasn't in the initializer. Now instead we simply use the
position of the subsequent parameter as the end of the initializer, which is
close enough.

Bug: chromium:902810
Change-Id: I8d2bc7a2dc9f59db16ce56ccef01e263a18a3b7a
Reviewed-on: https://chromium-review.googlesource.com/c/1326022Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57357}