Make jit/notes.txt better reflect current status quo

Make jit/notes.txt better reflect current status quo

gcc/jit/ChangeLog:
	* notes.txt: Show the beginning and ending of
	recording::context::compile vs playback::context::compile.  Show
	the creation and unlinking of the tempdir.  Show toplev::finalize.
	Move "RELEASE MUTEX" to the correct location.  Show
	gcc_jit_result_release, and indicate where the
	dlopen/dlsym/dlclose occur.

From-SVN: r218488