Emit a getMatchingSuperRegClass() implementation for every target.

Emit a getMatchingSuperRegClass() implementation for every target.

Use information computed while inferring new register classes to emit
accurate, table-driven implementations of getMatchingSuperRegClass().

Delete the old manual, error-prone implementations in the targets.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146873 91177308-0d34-0410-b5e6-96231b3b80d8