Together, these allow lldb-pdbdump to list all the modules from a PDB using a
native reader (rather than DIA).
Note that I'll probably be specializing NativeRawSymbol in a subsequent patch.
Differential Revision: https://reviews.llvm.org/D30956
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297883 91177308-0d34-0410-b5e6-96231b3b80d8
