The legacy pass is called "loop-unroll", but in the new PM it's called "unroll".
Also applied to unroll-and-jam and unroll-full.
Fixes various check-llvm tests when NPM is turned on.
Reviewed By: Whitney, dmgreen
Differential Revision: https://reviews.llvm.org/D82590
This makes sure to correctly register the loop info of the children
of unroll and jammed loops. It re-uses some code from the unroller for
registering subloops.
Differential Revision: https://reviews.llvm.org/D80619