Revert of [wasm] Fix I32ReinterpretF32 and I64ReinterpretF64 on ia32. (patchset #3 id:40001 of https://codereview.chromium.org/2639353002/ )

Reason for revert:
compilation problems on mips

Original issue's description:
> [wasm] Fix I32ReinterpretF32 and I64ReinterpretF64 on ia32.
>
> On ia32 return statements in C++ automatically convert signalling NaNs
> to quiet NaNs, even when bit_cast is used. This CL removes all uses of
> bit_cast<float> and bit_cast<double> in the wasm compiler and wasm
> interpreter.
>
> R=titzer@chromium.org, clemensh@chromium.org
>
> Review-Url: https://codereview.chromium.org/2639353002
> Cr-Commit-Position: refs/heads/master@{#42512}
> Committed: https://chromium.googlesource.com/v8/v8/+/7739affa5b57e0d28674d476f63de60d71728fb6

TBR=clemensh@chromium.org,titzer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review-Url: https://codereview.chromium.org/2645693003
Cr-Commit-Position: refs/heads/master@{#42514}