Add myself as SystemZ code owner

As agreed with Richard Sandiford, I'm taking over code ownership
for the SystemZ back end from him.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224535 91177308-0d34-0410-b5e6-96231b3b80d8
LiveIntervalAnalysis: Cleanup computeDeadValues

- This also fixes a bug introduced in r223880 where values were not
  correctly marked as Dead anymore.
- Cleanup computeDeadValues(): split up SubRange code variant, simplify
  arguments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224538 91177308-0d34-0410-b5e6-96231b3b80d8
[NFC] Removing extra semicolon.  

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224539 91177308-0d34-0410-b5e6-96231b3b80d8