[Stackmaps] Remove the liveness calculation for stackmap intrinsics.

There is no need to calculate the liveness information for stackmaps. The
liveness information is still available for the patchpoint intrinsic and
that is also the intended usage model.

Related to <rdar://problem/17473725>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211816 91177308-0d34-0410-b5e6-96231b3b80d8
[StackMaps] Enable patchpoint liveness analysis per default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211817 91177308-0d34-0410-b5e6-96231b3b80d8