ARM: Deduplicate ConstantPoolValues.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190779 91177308-0d34-0410-b5e6-96231b3b80d8
This patch implements Mips load/store instructions from/to coprocessor 2. Test cases are added.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190780 91177308-0d34-0410-b5e6-96231b3b80d8