PPC: Unify "runtime-style" IC functions with Runtime intrinsics

PPC: Unify "runtime-style" IC functions with Runtime intrinsics

Port bc8041dc2b4c8431c5c2476496acd3b7b8b3f61e

Original commit message:
    Previous to this CL, ICs used a slightly different code idiom
    to get to C++ code from generated code than runtime intrinsics,
    using an IC_Utility class that in essence provided exactly
    the same functionality as Runtime::FunctionForId, but in its
    own quirky way.

    This CL unifies the two mechanisms, folding IC_Utility
    away by making all IC entry points in C++ code, e.g. IC
    miss handlers, full-fledged runtime intrinsics. This makes
    it possible to eliminate a bunch of ad-hoc declarations and
    adapters that the IC system had to needlessly re-invent.

    As a bonus and the original reason for this yak-shave:
    IC-related C++ runtime functions are now callable from
    TurboFan.

R=danno@chromium.org, dstence@us.ibm.com, michael_dawson@ca.ibm.com
BUG=

Committed: https://crrev.com/1a57cede121f8c09af02f3f3e4959746b179b90b
Cr-Commit-Position: refs/heads/master@{#29821}

[dstence, 2015-07-23 15:44:17]

lgtm

[MTBrandyberry, 2015-07-23 15:51:08]

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

[commit-bot: I haz the power, 2015-07-23 15:51:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1249433004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1249433004/1

[commit-bot: I haz the power, 2015-07-23 16:23:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-23 16:23:21]

Patchset 1 (id:??) landed as
https://crrev.com/1a57cede121f8c09af02f3f3e4959746b179b90b
Cr-Commit-Position: refs/heads/master@{#29821}