Remove compressed (ETC1) texture support from Ganesh (take 2)

Reland of https://skia-review.googlesource.com/c/17456/ (Remove compressed (ETC1) texture support from Ganesh) but w/o removing third_part\etc1 files

TBR=bsalomon@google.com
Change-Id: I8ec4b7e3ddf47d213cb24c382731c050ffb8847f
Reviewed-on: https://skia-review.googlesource.com/17700
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
27 files changed