[RewriteStatepointsForGC] Yet more test cases for relocation

At this point, we should have decent coverage of the involved code.  I've got a few more test cases to cleanup and submit, but what's here is already reasonable.

I've got a collection of liveness tests which will be posted for review along with a decent liveness algorithm in the next few days.  Once those are in, the code in this file should be well tested and I can start renaming things without risk of serious breakage.  

llvm-svn: 231414