[dsymutil] Store an optional BinaryPath in the debug map.

[dsymutil] Store an optional BinaryPath in the debug map.

llvm-dsymutil needs to emit dSYM companion bundles. These are binary files
that replicate some of the orignal binary file properties (sections and
symbols). To get acces to these properties, pass the binary path in the
debug map.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246011 91177308-0d34-0410-b5e6-96231b3b80d8