[X86][SchedModel] Add missing scheduling model for SSE related instructions.

The patch defines new or refines existing generic scheduling classes to match
the behavior of the SSE instructions.
It also maps those scheduling classes on the related SSE instructions.

<rdar://problem/15607571>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202065 91177308-0d34-0410-b5e6-96231b3b80d8