Always call endFlush on opLists that might survive a flush

We were missing a few that got unreffed due to failed proxy
instantiation.

Bug: skia:7655
Bug: skia:7111
Change-Id: I95847a16890f2993a1433d4d9fdaa8a4a6c2f0b6
Reviewed-on: https://skia-review.googlesource.com/122121
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
6 files changed