Since explicit allocation is always enabled now, the resource allocator explicitly manages reuse of GrSurfaces and this flag isn't used/needed.
Change-Id: I5703bf4624e21f9aff9da76575f4ef757b1d2589
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/210140
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>