Stop DSLParser from continuing after an invalid token

This matches the behavior of SkSLParser

Change-Id: Ib9af7173dda8866faf8633b8c88a8716b4e6b8d4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/443239
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
1 file changed