Add inequality operator for MachineLocation.

Fixes the build I broke in r205360

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205361 91177308-0d34-0410-b5e6-96231b3b80d8
Refactor out the comparison of the location/value in a DebugLocEntry

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205364 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unused function DebugLocEntry::isEmpty

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205365 91177308-0d34-0410-b5e6-96231b3b80d8