Sub-minor-key-ify seven HydrogenCodeStubs.

- FastCloneShallowObjectStub
- StringAddStub
- LoadFastElementStub
- StoreFastElementStub
- TransitionElementsKindStub
- ArrayConstructorStubBase
- InternalArrayConstructorStubBase

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/511853002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23477 ce2b1a6d-e550-0410-aec6-3dcde31c8c00