Removed unnecessary check in DSLWriter::Var

This was causing problems in the upcoming error reporting code and does
not appear to be doing anything useful anymore.

Change-Id: Ic4069d9c085e291907483c6019f49a089ee9370d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/435796
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
1 file changed