More ctype cleanup in SkSL

- Remove ctypes that were entirely unused
- Remove explicit selection of default ctypes
- After that, only two ctype tokens are needed (SkPMColor4f and SkV4)
  ... remove all of the others from the parser

Change-Id: I2322aab73a19127b3b26850aefdad6140ea0f7e7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/410057
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
12 files changed