Remove "buffer" modifier from SkSL

Change-Id: I4df18946cdb3d9f1f7833461f913f2df94696821
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/372197
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
14 files changed