ARM Scheduler Model: Partial implementation of the new machine scheduler model

This is very much work in progress. Please send me a note if you start to depend
on the added abstract read/write resources. They are subject to change until
further notice.

The old itinerary is still the default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177967 91177308-0d34-0410-b5e6-96231b3b80d8
ARM Scheduler Model: Add resources instructions, map resources in subtargets

Move the CortexA9 resources into the CortexA9 SchedModel namespace. Define
resource mappings under the CortexA9 SchedModel. Define resources and mappings
for the SwiftModel.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177968 91177308-0d34-0410-b5e6-96231b3b80d8