[turbofan] Enable tail calls for %_CallFunction.

[turbofan] Enable tail calls for %_CallRuntime.

This involves:
- Enabling the tail call optimization reducer in all cases.
- Adding an addition flag to CallFunctionParameters to mark call sites
  that can be tail-called enabled.
- Only set the tail-call flag for %_CallFunction.

R=bmeurer@chromium.org

Committed: https://crrev.com/1fa4285e1ce16cfadf8c40a0993491ec4e2bbbe0
Cr-Commit-Position: refs/heads/master@{#29436}

[danno, 2015-07-01 16:27:26]

danno@chromium.org changed reviewers:
+ bmeurer@chromium.org

[danno, 2015-07-01 16:27:26]

PTAL

[Benedikt Meurer, 2015-07-02 04:07:45]

LGTM.

[danno, 2015-07-02 05:58:12]

The CQ bit was checked by danno@chromium.org

[commit-bot: I haz the power, 2015-07-02 05:58:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1216933011/40001

[commit-bot: I haz the power, 2015-07-02 06:20:08]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-07-02 06:20:21]

Patchset 3 (id:??) landed as
https://crrev.com/1fa4285e1ce16cfadf8c40a0993491ec4e2bbbe0
Cr-Commit-Position: refs/heads/master@{#29436}