PPC: Use big-boy Types to annotate interface descriptor parameters

PPC: Use big-boy Types to annotate interface descriptor parameters

Port c019d7f498ce6fbac6659924e20ddb6c59aebeb8

Original commit message:
- Thread Type::FunctionType through stubs and the TF pipeline.
- Augment Typer to decorate parameter nodes with types from
  a Type::FunctionType associated with interface descriptors.
- Factor interface descriptors into platform-specific and
  platform-independent components so that all descriptors share
  a common Type::FunctionType for all platforms.

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

Committed: https://crrev.com/5989a374c95f9f138b4953e5f801c5d368acfe8a
Cr-Commit-Position: refs/heads/master@{#29257}

[dstence, 2015-06-24 15:38:42]

lgtm

[MTBrandyberry, 2015-06-24 15:42:22]

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

[commit-bot: I haz the power, 2015-06-24 15:42:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1206893002/20001

[commit-bot: I haz the power, 2015-06-24 16:10:01]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-06-24 16:10:18]

Patchset 2 (id:??) landed as
https://crrev.com/5989a374c95f9f138b4953e5f801c5d368acfe8a
Cr-Commit-Position: refs/heads/master@{#29257}