Add fast path for tail insertion in GrResourceAllocator::IntervalList

Change-Id: I8953036d61b4ea4989c8722f536db9cd520a1e24
Reviewed-on: https://skia-review.googlesource.com/146167
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
2 files changed