This avoids a situation where we didn't know the position of a postfix
expression while we were in the middle of evaluating it, which was
leading to problems with upcoming error reporting changes.
Change-Id: Ie6d4dd8411ffb24ac7ee95d3e908483d0d92ba0f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/527499
Reviewed-by: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
59b0688e5e