Get EGLimage functions out of GrGLInterface.

Only used in test code which can just directly call these.

Also removed related code in interface assemble/validate generator.

Change-Id: I7e821ebb9328bdd2a54d8ab3af929399ca0517d5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/213480
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
8 files changed