Fixed pthread_spin_lock on sparc32/64 (bug 16882)

	[BZ #16882]
	* nptl/sysdeps/sparc/sparc32/pthread_spin_lock.S
	(pthread_spin_lock): Branch out of spin loop to proper location.
	* nptl/sysdeps/sparc/sparc64/pthread_spin_lock.S
	(pthread_spin_lock): Likewise.
New test for pthread_spin_lock (bug 16882)

	* nptl/tst-spin4.c: New test.
	* nptl/Makefile (tests): Add tst-spin4.
Fixup ChangeLog and add missing NEWS entry for previous commits.