Add Kawase blur with dual filtering

Blurs are smoother between R=50 to R=200 with similar performance to
the previous version. We use between 1 and 5 passes at progressively
smaller resolutions depending on the blur radius that was requested.

This is currently not enabled in code, but will be enabled by a
follow-up CL.

Test: atest BlurTests
Bug: 185365391
Flag: EXEMPT already behind a non-aconfig flag
Change-Id: I2ad47d83b69b69215fe59a5ecda3b1766177a852