[turbofan] Add bounds check to Node::InputAt(index) and fix tests that go out of bounds.

[turbofan] Add bounds check to Node::InputAt(index) and fix tests that go out of bounds.

BUG=

Committed: https://crrev.com/41795b8ae217271ff8cd1299716a8cd5f29dadc4
Cr-Commit-Position: refs/heads/master@{#28540}

[titzer, 2015-05-20 18:50:35]

titzer@chromium.org changed reviewers:
+ mstarzinger@chromium.org

[Michael Starzinger, 2015-05-21 07:56:11]

LGTM.

[titzer, 2015-05-21 07:58:46]

The CQ bit was checked by titzer@chromium.org

[commit-bot: I haz the power, 2015-05-21 07:58:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1149563004/1

[commit-bot: I haz the power, 2015-05-21 08:19:55]

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

[commit-bot: I haz the power, 2015-05-21 08:19:56]

Try jobs failed on following builders:
  v8_linux_arm64_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel/builds/5890)

[titzer, 2015-05-21 10:53:50]

The CQ bit was checked by titzer@chromium.org

[titzer, 2015-05-21 10:53:50]

The patchset sent to the CQ was uploaded after l-g-t-m from
mstarzinger@chromium.org
Link to the patchset: https://codereview.chromium.org/1149563004/#ps20001
(title: " ")

[commit-bot: I haz the power, 2015-05-21 10:53:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1149563004/20001

[commit-bot: I haz the power, 2015-05-21 11:00:04]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-21 11:00:22]

Patchset 2 (id:??) landed as
https://crrev.com/41795b8ae217271ff8cd1299716a8cd5f29dadc4
Cr-Commit-Position: refs/heads/master@{#28540}