Fix a GrThreadSafeUniquelyKeyedProxyViewCache test

I broke this when I switched over to the SkTDynamicHash

Bug: 1108408
Change-Id: I906b41330440d084ba2e97c0162af38a79da0529
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/318696
Reviewed-by: Adlai Holler <adlai@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
4 files changed