Blocks did not previously track their position, creating problems
reporting some errors (which will be improved in followup CLs). Fixing
block positions changed the reporting of do loop errors, requiring do
loop position tracking to be updated as part of this change.
Change-Id: I3bd048a62d912914edf679f42607de1b5eafc2b9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/528045
Reviewed-by: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
f125d4e7a0