[graphite] Replace GrSLType with SkSLType

This is mostly mechanical. The only interesting bit is that GrSLType was in include/private while SkSLType is in src/core so some #include patterns changed.

Bug: skia:12701
Change-Id: I80bd86ee93796b145f86ded9b4cbf52f24fa59e5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/497607
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
94 files changed