ARM: Add scheduling information for LDRLIT instructions to swift scheduling model

ARM: Add scheduling information for LDRLIT instructions to swift scheduling model

These pseudo instructions are only lowered after register allocation and
are therefore still present when the machine scheduler runs.
Add a run: line to a testcase that uses the uncommon flags necessary to
actually produce a LDRLIT instruction on swift.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242587 91177308-0d34-0410-b5e6-96231b3b80d8