Merging r230058 by d0k:

LoopRotate: When reconstructing loop simplify form don't split edges
from indirectbrs.

Yet another chapter in the endless story. While this looks like we leave
the loop in a non-canonical state this replicates the logic in
LoopSimplify so it doesn't diverge from the canonical form in any way.

PR21968


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_36@231698 91177308-0d34-0410-b5e6-96231b3b80d8