Revert a hunk from 9634064c

This causes errors when building LLDB because the Windows implementation
doesn't implement this method:

C:\src\llvm-project\lldb\source\Plugins\ScriptInterpreter\Python\ScriptInterpreterPython.cpp(915,19): error: allocating an object of abstract class type 'lldb_private::ConnectionGenericFile'
              new ConnectionGenericFile(read_file, true));
                  ^
C:\src\llvm-project\lldb\include\lldb/Utility/Connection.h(174,28): note: unimplemented pure virtual method 'GetReadObject' in 'ConnectionGenericFile'
  virtual lldb::IOObjectSP GetReadObject() = 0;
                           ^