Revert "Revert "Refactored SPIR-V RelaxedPrecision handling""

This reverts commit a9c187e5ccd5596e8f2f988b4e73977abadd4995.

Change-Id: Icbfb8abdfc67fc2e6428d97a6cdede2726fb56e4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/385596
Auto-Submit: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
218 files changed