Revert of skcpu: sse4.1 floor, f16c f16<->f32 (patchset #11 id:200001 of https:/...

Revert of skcpu: sse4.1 floor, f16c f16<->f32 (patchset #11 id:200001 of https://codereview.chromium.org/1891513002/ )

Reason for revert:
this depends on a CL I want to revert

Original issue's description:
> skcpu: sse4.1 floor, f16c f16<->f32
>
>   -  floor with roundps is about 4.5x faster when available
>   -  f16 srcover_n is similar to but a little faster than the version in https://codereview.chromium.org/1884683002.  This new one fuses the dst load/stores into the f16<->f32 conversions:
>
> +0x180	    movups              (%r15), %xmm1
> +0x184	    vcvtph2ps           (%rbx), %xmm2
> +0x189	    movaps              %xmm1, %xmm3
> +0x18c	    shufps              $255, %xmm3, %xmm3
> +0x190	    movaps              %xmm0, %xmm4
> +0x193	    subps               %xmm3, %xmm4
> +0x196	    mulps               %xmm2, %xmm4
> +0x199	    addps               %xmm1, %xmm4
> +0x19c	    vcvtps2ph           $0, %xmm4, (%rbx)
> +0x1a2	    addq                $16, %r15
> +0x1a6	    addq                $8, %rbx
> +0x1aa	    decl                %r14d
> +0x1ad	    jne                 +0x180
>
> If we decide to land this it'd be a good idea to convert most or all users of SkFloatToHalf_01 and SkHalfToFloat_01 over to the pointer-based versions.
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1891513002
> CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot
>
> Committed: https://skia.googlesource.com/skia/+/cbe3c1af987d622ea67ef560d855b41bb14a0ce9
>
> Committed: https://skia.googlesource.com/skia/+/3faf74b8364491ca806f523fbb1d8a97be592663

TBR=fmalita@chromium.org,herb@google.com,reed@google.com,mtklein@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1897433002