* lib/mi-support.exp: Expand comments about PATH_EXPR.

	* lib/mi-support.exp: Expand comments about PATH_EXPR.
	(varobj_tree::get_path_expr): Assume that all varobjs are
	compound unless they are known simple types.
	Adjust path expressions based on parent type, path parent type,
	and tree language.
	(varobj_tree::walk_tree): Add LANGUAGE parameter and save it into
	the root varobj.
	(mi_walk_varobj_tree): Add LANGUAGE parameter.