[lldb][asan] Mark destructor as virtual to allow subclasses.

`lldb_private::ScriptInterpreterPython::CommandDataPython` inherits from `lldb_private::BreakpointOptions::CommandData`, but the latter does not have a virtual destructor. This leads to a new-delete-type-mismatch error when running certain tests (such as `functionalities/breakpoint/breakpoint_command/TestBreakpointCommand.py`) under asan.