remove SkTLS

  - used for debug lock tracking in SkFont*
  - used for debug logging in SkPathOps
  - genuine use in GLTestContext_cmd_buf?
    switched that to thread_local
  - keep empty SkTLS_{pthread,win}.cpp until
    references to them can be cleaned up

Bug: skia:10006
Change-Id: I195a94c95d3f1a1918ee8c9bc4a15fa5b4344fbc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/275282
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
25 files changed