Revert of Expand _01 half<->float limitation to _finite.  Simplify. (patchset #7 id:120001 of https://codereview.chromium.org/2145663003/ )

Reason for revert:
Unit tests fail on Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-Fast

Original issue's description:
> Expand _01 half<->float limitation to _finite.  Simplify.
>
>     It's become clear we need to sometimes deal with values <0 or >1.
>     I'm not yet convinced we care about NaN or +-inf.
>
>     We had some fairly clever tricks and optimizations here for NEON
>     and SSE.  I've thrown them out in favor of a single implementation.
>     If we find the specializations mattered, we can certainly figure out
>     how to extend them to this new range/domain.
>
>     This happens to add a vectorized float -> half for ARMv7, which was
>     missing from the _01 version.  (The SSE strategy was not portable to
>     platforms that flush denorm floats to zero.)
>
>     I've tested the full float range for FloatToHalf on my desktop and a 5x.
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2145663003
> CQ_INCLUDE_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot;master.client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot,Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-Fast-Trybot
>
> Committed: https://skia.googlesource.com/skia/+/3296bee70d074bb8094b3229dbe12fa016657e90

TBR=msarett@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/2151023003
11 files changed