Remove a leading $ during name mangling.

If SkSL inlined a private function, its name mangled version was coming
out as `_123_$function` which isn't a legal symbol name.

Change-Id: I2317731479b31c2edf6ff7e34997807dc8a0c488
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/526459
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
1 file changed