Revert of impl colormatrix w/ floats (patchset #7 id:120001 of https://codereview.chromium.org/967943002/)

Reason for revert:
Arm64 seems to be having glitches :(

See gm:colormatrix on Arm64/TegraK1/Nexus9

last square should be all white, but it has stripes

Original issue's description:
> impl colormatrix w/ floats
>
> this needs to land first https://codereview.chromium.org/1031713003
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/7971def11be91ed08eae7107b372322d24e67544

TBR=mtklein@google.com,caryclark@google.com,reed@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1030743003
4 files changed