Remove unused struct/enum

Patch by Matthias Braun!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188388 91177308-0d34-0410-b5e6-96231b3b80d8
LiveIntervalUnion is not used in RegAllocBase.

Patch by Matthias Braun!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188389 91177308-0d34-0410-b5e6-96231b3b80d8
Remove declaration of nonexistant function.

Patch by Matthias Braun!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188390 91177308-0d34-0410-b5e6-96231b3b80d8
Improve misleading comment.

Patch by Matthias Braun!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188391 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unused function.

Patch by Matthias Braun!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188392 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unnecessary parameter to RenumberValues.

Patch by Matthias Braun!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188393 91177308-0d34-0410-b5e6-96231b3b80d8