[turbofan] Fix OSR entry in case label.

[turbofan] Fix OSR entry in case label.

With do-expressions any expression used as a case label can turn into an
OSR entry-point. This means the value being switched over is renamed to
an OSR value and needs to be reloaded from the environment at each case.

R=rossberg@chromium.org
TEST=mjsunit/regress/regress-osr-in-case-label

Committed: https://crrev.com/c42f188ce2dca1546f9578747f90438d0907b24c
Cr-Commit-Position: refs/heads/master@{#31986}

[Michael Starzinger, 2015-11-13 14:48:06]

Who needs ClusterFuzz? :P

[rossberg, 2015-11-13 14:50:05]

lgtm

[Michael Starzinger, 2015-11-13 14:54:43]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2015-11-13 14:54:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1438123007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1438123007/1

[commit-bot: I haz the power, 2015-11-13 15:02:21]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-11-13 15:02:21]

Try jobs failed on following builders:
  v8_linux_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_rel/builds/11705)

[Michael Starzinger, 2015-11-13 15:55:10]

The CQ bit was checked by mstarzinger@chromium.org

[Michael Starzinger, 2015-11-13 15:55:10]

The patchset sent to the CQ was uploaded after l-g-t-m from
rossberg@chromium.org
Link to the patchset: https://codereview.chromium.org/1438123007/#ps20001
(title: "Skip for ignition.")

[commit-bot: I haz the power, 2015-11-13 15:55:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1438123007/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1438123007/20001

[commit-bot: I haz the power, 2015-11-13 16:04:59]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-11-14 23:21:38]

Patchset 2 (id:??) landed as
https://crrev.com/c42f188ce2dca1546f9578747f90438d0907b24c
Cr-Commit-Position: refs/heads/master@{#31986}