LiveIntervals: Fix handleMoveUp with subreg def moving across a def

LiveIntervals: Fix handleMoveUp with subreg def moving across a def

If a subregister def was moved across another subregister def and
another use, the main range was not correctly updated. The end point
of the moved interval ended too early and missed the use from theh
other lanes in the subreg def.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375300 91177308-0d34-0410-b5e6-96231b3b80d8