[graphite] Add basic Recorder-level proxy caching

This is an extremely basic cache and, in fact, never removes a cached proxy!

On the desk_motionmarksuits.skp with the grmtl config this caching gives us:

                min 	median	mean	max	stddev
w/o caching   11.1ms	11.2ms	11.2ms	11.4ms	1%
w/ caching    6.78ms	6.87ms	6.95ms	7.35ms	3%

Bug: skia:14212
Bug: b/256870077
Change-Id: I894c206709bce96a85014e5da897274d12c7340a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/662676
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
5 files changed