Set the encoding bits to {0,?,?,0}, not 0. Plus delegate the disassembly of ADR to
the more generic ADDri/SUBri instructions, and add a test case for that.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128234 91177308-0d34-0410-b5e6-96231b3b80d8