Some cleanup of unneeded code/objects in GrVkPipelineState.

I wanted to cleanup this file as much as possible before starting to add
caching logic to make the changes simpler.

Bug: skia:9574
Change-Id: I8280a81f17372680a488f7f7d28d78d68121b235
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/251201
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
4 files changed