Add missing GrGLCaps logs

I tried to keep the log statements in line with the caps fields
themselves.

Also removed an unused cap.

Change-Id: I7b7f2ec0320fc72b57dc104be41ee7b5d12e6415
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/399741
Commit-Queue: Adlai Holler <adlai@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
Auto-Submit: Adlai Holler <adlai@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
2 files changed