second guess swizzler avx-512 opts
second guess swizzler avx-512 opts

Like the last CL, not sure these outperform AVX2, and if they don't
they're either dead code or a risk that clocks the CPU down.

Best comparison chart I have to watch, where AVX-512 once again looks
worse than AVX2 at head:

    https://perf.skia.org/e/?formulas=geo(filter(%22bench_type%3Dskcodec%26cpu_or_gpu_value%3DAVX2%26extra_config%3D!Fast%26extra_config%3D!SK_FORCE_RASTER_PIPELINE_BLITTER%26model%3DGCE%22))&formulas=geo(filter(%22bench_type%3Dskcodec%26cpu_or_gpu_value%3DAVX512%26extra_config%3D!Fast%26extra_config%3D!SK_FORCE_RASTER_PIPELINE_BLITTER%26model%3DGCE%22))&formulas=geo(filter(%22bench_type%3Dskcodec%26cpu_or_gpu_value%3DAVX512%22))

Change-Id: Ia772ae0b5c7a96355fac36d55ebb224f6d42dd4c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/313865
Reviewed-by: Herb Derby <9e12a3d2bbf73546e47cc9958f6ba8f3215b7eaf@google.com>
Commit-Queue: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>

google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia