Fix R2RDump test in CG2 pipelines (#44460)

Fix R2RDump test in CG2 pipelines (#44460)

Our scripts normally assume that all test projects are at least
two nesting levels deep under $(TestBinDir); the r2rdump test was
violating that and, in doing so, it was triggering a failure in
CG2 compilation.

After I decided to fix this by moving the r2rdump folder under
"readytorun" I found out that there already is a r2rdump folder
there - apparently Amy during her initial R2RDump implementation
authored a basic test suite even though it's disabled right now.

I have resolved this by moving the original test under
"readytorun/r2rdump" to "readytorun/r2rdump/BasicTests" and I moved
Andrew's new test under "readytorun/r2rdump/FrameworkTests".
I'm not super happy about the naming but I don't have any better
ideas at the moment, I'll be happy to improve this based on PR
feedback.

Thanks

Tomas