Fix j1, jn missing errno setting on underflow (bug 18611).

j1 and jn can underflow for small arguments, but fail to set errno
when underflowing to 0.  This patch fixes them to set errno in that
case.

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #18611]
	* sysdeps/ieee754/dbl-64/e_j1.c (__ieee754_j1): Set errno and
	avoid excess range and precision on underflow.
	* sysdeps/ieee754/dbl-64/e_jn.c (__ieee754_jn): Likewise.
	* sysdeps/ieee754/flt-32/e_j1f.c (__ieee754_j1f): Likewise.
	* sysdeps/ieee754/flt-32/e_jnf.c (__ieee754_jnf): Likewise.
	* sysdeps/ieee754/ldbl-128/e_j1l.c (__ieee754_j1l): Set errno on
	underflow.
	* sysdeps/ieee754/ldbl-128/e_jnl.c (__ieee754_jnl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_jnl.c (__ieee754_jnl): Likewise.
	* sysdeps/ieee754/ldbl-96/e_j1l.c (__ieee754_j1l): Likewise.
	* sysdeps/ieee754/ldbl-96/e_jnl.c (__ieee754_jnl): Likewise.
	* math/auto-libm-test-in: Do not allow missing errno setting for
	tests of j1 and jn.
	* math/auto-libm-test-out: Regenerated.