Don't count debug instructions towards neighborhood count

In computeRegisterLiveness, the max instructions to search
was counting dbg_value instructions, which could potentially
cause an observable codegen change from the presence of debug
info.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341028 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed