[WebAssembly] Speed up LiveIntervals updating.

Use the more specific LiveInterval::removeSegment instead of
LiveInterval::shrinkToUses when we know the specific range that's
being removed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270463 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed