Made out-of-bounds literals non-fatal errors in DSLParser

There was no good reason for this behavior in the first place, and this
change makes the error reporting behavior better match SkSLParser.

Change-Id: I7b69e7bcc64173c0ac6523e075c1f24e2be00ed0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/444758
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
1 file changed