Version 3.28.28.2 (merged r22456)

MIPS: StubCallInterfaceDescriptor and CallInterfaceDescriptor are unified under a base class InterfaceDescriptor.

R=jkummerow@chromium.org, machenbach@chromium.org
BUG=

Review URL: https://codereview.chromium.org/404773002

git-svn-id: https://v8.googlecode.com/svn/trunk@22479 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/trunk' into trunk