Debug info: Fix PR16736 and rdar://problem/14990587.
A DBG_VALUE is register-indirect iff the first operand is a register
_and_ the second operand is an immediate.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190821 91177308-0d34-0410-b5e6-96231b3b80d8