remove incorrect line number from SkSL errors with no source information

Change-Id: Ib9117dbd1bcd2c3581fba02416d9eabda1dfc6dd
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/341458
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
38 files changed