Revert of [x64] Improve instruction selection for TruncateInt64ToInt32.

Revert of [x64] Improve instruction selection for TruncateInt64ToInt32. (patchset #1 id:1 of https://codereview.chromium.org/936323004/)

Reason for revert:
Breaks SQLite

Original issue's description:
> [x64] Improve instruction selection for TruncateInt64ToInt32.
>
> R=svenpanne@chromium.org
>
> Committed: https://crrev.com/64a2717529e2197f3a789adabf86ca36f5eb764c
> Cr-Commit-Position: refs/heads/master@{#26739}

TBR=svenpanne@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/61ac461330d7f9cf36a71a6f8cff6c47857ed02a
Cr-Commit-Position: refs/heads/master@{#26791}

[Benedikt Meurer, 2015-02-23 07:08:26]

Created Revert of [x64] Improve instruction selection for TruncateInt64ToInt32.

[commit-bot: I haz the power, 2015-02-23 07:09:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/928723003/1

[commit-bot: I haz the power, 2015-02-23 07:09:19]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-23 07:09:23]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-23 07:09:37]

Patchset 1 (id:??) landed as
https://crrev.com/61ac461330d7f9cf36a71a6f8cff6c47857ed02a
Cr-Commit-Position: refs/heads/master@{#26791}

[Michael Achenbach, 2015-02-23 09:26:31]

Is this revert required to be merged back to 4.2?

[Benedikt Meurer, 2015-02-23 09:26:56]

Probably, yes.