Revert of [turbofan] Implemented the TruncateFloat32ToInt64 TurboFan operator. (patchset #1 id:1 of https://codereview.chromium.org/1476063002/ )

Reason for revert:
Unexpected error occurred.

Original issue's description:
> [turbofan] Implemented the TruncateFloat32ToInt64 TurboFan operator.
>
> The TruncateFloat32ToInt64 operator converts a float32 to an int64 using
> the round-to-zero rounding mode (truncate). If the input value is
> outside the int64 range, then the result depends on the architecture. I
> implemented the operator on x64, arm64, and mips64.
>
> R=titzer@chromium.org, jacob.bramley@arm.com
>
> Committed: https://crrev.com/1df1066c3c77464d2a68d7c8d501a5a0f3ad195a
> Cr-Commit-Position: refs/heads/master@{#32315}

TBR=jacob.bramley@arm.com,titzer@chromium.org,v8-mips-ports@googlegroups.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1475343002

Cr-Commit-Position: refs/heads/master@{#32316}