This is combination of following changes,
- Resolve function symbols in PDB symbol file. lldb-test symbols will display information about function symbols.
- Implement SymbolFilePDB::FindFunctions methods. On lldb console, searching function symbol by name and by regular expression are both available.
- Create lldb type for PDBSymbolFunc.
- Add tests to check whether functions with the same name but from different sources can be resolved correctly.