Fix a comment in configure.ac

The relevant code in jit/internal-api.c was moved to jit/jit-playback.c
in 3071567787aef4a8ada8b38c890d01c19b4b998f.

gcc/ChangeLog.jit:
	* configure.ac: Update a reference to jit/internal-api.c to
	jit/jit-playback.c.
	* configure: Regenerate.