added SPIR-V persistent cache support for Vulkan

Bug: skia:
Change-Id: Iec9053655f6ec2cc49a90c4b686995feaff6e488
Reviewed-on: https://skia-review.googlesource.com/c/178923
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
7 files changed