PPC: [turbofan] Better and more sane support for tail calls

PPC: [turbofan] Better and more sane support for tail calls

Port ff283f7ded84df5a5a77d088e37fd69cf6271a8c

Original commit message:
    * Limit triggering of tail calls to explicit use of a new inline runtime
      function %_TailCall. %_TailCall works just like %_Call except for using
      tail-calling mechanics (currently only in TF).
    * Remove hack that recognized some specific usages of %_Call and converted them
      into tail calls.
    * Support tail calls for all calls where the number of callee stack parameters
      is less than or equal to the number of caller stack parameters.
    * Use the gap resolver to swizzle parameters and registers to tail calls.

R=danno@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, dstence@us.ibm.com
BUG=v8:4076
LOG=n

Committed: https://crrev.com/cf2f6b80cb4bfe57fb10f509eb1077995aec9322
Cr-Commit-Position: refs/heads/master@{#31994}

[michael_dawson, 2015-11-13 19:51:16]

On 2015/11/13 19:44:00, mtbrandyberry wrote:

lgtm

[MTBrandyberry, 2015-11-13 19:59:06]

The CQ bit was checked by mbrandy@us.ibm.com

[commit-bot: I haz the power, 2015-11-13 19:59:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1442143002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1442143002/1

[commit-bot: I haz the power, 2015-11-13 20:36:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-14 23:21:58]

Patchset 1 (id:??) landed as
https://crrev.com/cf2f6b80cb4bfe57fb10f509eb1077995aec9322
Cr-Commit-Position: refs/heads/master@{#31994}