MIPS: Remove unused J(Label *).

MIPS: Remove unused J(Label *).

Remove unused macro-asm instruction and associated address patching.

On mips64, remove unused JumpLabelToJumpRegister(). On mips, rename
it appropriately (it's still used there for JR->J optimizations).

BUG=

Committed: https://crrev.com/0f0ce4a9c63054d41fe0764e0591696b556ceaa5
Cr-Commit-Position: refs/heads/master@{#27593}

[paul.l..., 2015-04-02 17:06:50]

paul.lind@imgtec.com changed reviewers:
+ akos.palfi@imgtec.com, balazs.kilvady@imgtec.com, danno@chromium.org,
dusan.milosavljevic@imgtec.com

[paul.l..., 2015-04-02 17:06:50]

PTAL.

[balazs.kilvady, 2015-04-02 17:31:21]

LGTM.

[paul.l..., 2015-04-02 17:36:28]

The CQ bit was checked by paul.lind@imgtec.com

[commit-bot: I haz the power, 2015-04-02 17:36:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1059433003/40001

[commit-bot: I haz the power, 2015-04-02 18:45:10]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-04-02 18:45:19]

Patchset 3 (id:??) landed as
https://crrev.com/0f0ce4a9c63054d41fe0764e0591696b556ceaa5
Cr-Commit-Position: refs/heads/master@{#27593}