Fix a problem exposed by the local allocator. CALL instructions are not marked

Fix a problem exposed by the local allocator.  CALL instructions are not marked
as using incoming argument registers, so the local allocator would clobber them
between their set and use.  To fix this, we give the call instructions a variable
number of uses in the CALL MachineInstr itself, so live variables understands
the live ranges of these register arguments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28744 91177308-0d34-0410-b5e6-96231b3b80d8