[arm] Fix --enable-vldr-imm.

[arm] Fix --enable-vldr-imm.

This fixes several bugs related to float64 pool constants.

Note that float64 pool constants are still disabled by default, and are
only used if --enable-vldr-imm is provided.

BUG=

Committed: https://crrev.com/def86473440908ca93795bb3af515a721f4583cf
Cr-Commit-Position: refs/heads/master@{#29917}

[jbramley, 2015-07-28 09:51:48]

jacob.bramley@arm.com changed reviewers:
+ bmeurer@chromium.org, ulan@chromium.org, yangguo@chromium.org

[Benedikt Meurer, 2015-07-28 10:41:57]

LGTM from my side.

[ulan, 2015-07-28 10:56:58]

lgtm

[Yang, 2015-07-28 10:58:42]

On 2015/07/28 10:56:58, ulan wrote:
> lgtm

lgtm.

[Yang, 2015-07-28 10:58:42]

On 2015/07/28 10:56:58, ulan wrote:
> lgtm

lgtm.

[jbramley, 2015-07-28 10:59:39]

The CQ bit was checked by jacob.bramley@arm.com

[commit-bot: I haz the power, 2015-07-28 10:59:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1260953002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1260953002/1

[commit-bot: I haz the power, 2015-07-30 09:11:15]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-30 09:11:39]

Patchset 1 (id:??) landed as
https://crrev.com/def86473440908ca93795bb3af515a721f4583cf
Cr-Commit-Position: refs/heads/master@{#29917}