[dsymutil] Add DebugMapObject::lookupObjectAddress()

It turns out the debug map will be interogated both by name and
by object file address. Add the latter capability.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229177 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed