Fix line numbering problem when reporting SkSL compile errors

We were pretty-printing the source after feeding it to the compiler, so
line numbers didn't match up. Instead, pretty-print before compilation
(but only in debug builds), and remove any reformatting that happens
downstream.

Change-Id: I2b032ed01f725ca27e17436510d93505f7924aa5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/218961
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2 files changed