PPC: Reland Vector ICs: platform support for vector-based stores.

PPC: Reland Vector ICs: platform support for vector-based stores.

Port 40fbed0609ddb3e4ee4338049383004b62d13853

Original commit message:
    The last changes for vector store functionality, they are in 3 areas:

    1) The new vector [keyed] store code stubs - implementation.
    2) IC and handler compiler adjustments
    3) Odds and ends. A change in ast.cc, a test update, a small Oracle fix.

R=mvstanton@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, dstence@us.ibm.com
BUG=

Committed: https://crrev.com/1b191a5d72511dc3662a65ee2c4256663b043975
Cr-Commit-Position: refs/heads/master@{#30657}

[dstence, 2015-09-09 13:50:11]

lgtm

[MTBrandyberry, 2015-09-09 14:04:17]

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

[commit-bot: I haz the power, 2015-09-09 14:04:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1330883002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1330883002/1

[commit-bot: I haz the power, 2015-09-09 14:42:56]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-09 14:43:15]

Patchset 1 (id:??) landed as
https://crrev.com/1b191a5d72511dc3662a65ee2c4256663b043975
Cr-Commit-Position: refs/heads/master@{#30657}