[AArch64][CollectLOH] Fix a regression that prevented us to detect chains of
more than 2 instructions.

I introduced this regression a while back and did not noticed it because I
somehow forgot to push the initial test cases for the pass!

Fix that as well!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246239 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed