[MachineOutliner] Outline both register save calls + no LR save calls together

Instead of treating the outlined functions for these as distinct frames, they
should be combined into one case. Neither allows for stack fixups, and both
generate the same frame. Thus, they ought to be considered one case.

This makes the code far easier to understand, for one thing. It also offers
some small code size improvements. It's fairly rare to see a class of outlined
functions that doesn't fall entirely into one variant (on CTMark anyway). It
does happen from time to time though.

This mostly offers some serious simplification.

Also update the test to show the added functionality.

llvm-svn: 348036