Safeguard DBG_VALUE handling. Unbreaks the ASAN buildbot.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186014 91177308-0d34-0410-b5e6-96231b3b80d8
Use the appropriate unsigned int type for the offset.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186015 91177308-0d34-0410-b5e6-96231b3b80d8