pre-RA-sched assertion fix. This bug was exposed by r176037.

rdar:13370002 [pre-RA-sched] assertion: released too many times

I tracked this down to an earlier hack that is no longer applicable
and interfered with normal scheduler logic. With the changes in
r176037, it was causing an instruction to be scheduled multiple times.

I have an external test case that I tried hard to reduce and
failed. I can't even reproduce with llc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176636 91177308-0d34-0410-b5e6-96231b3b80d8
Hexagon: Add support to lower block address.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176637 91177308-0d34-0410-b5e6-96231b3b80d8
pre-RA-sched debug-only fix

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176638 91177308-0d34-0410-b5e6-96231b3b80d8