Fix log1pl (LDBL_MAX) in FE_UPWARD mode (bug 16564).

Fix log1pl (LDBL_MAX) in FE_UPWARD mode (bug 16564).

Bug 16564 is spurious overflow of log1pl (LDBL_MAX) in FE_UPWARD mode,
resulting from log1pl adding 1 to its argument (for arguments not
close to 0), which overflows in that mode.  This patch fixes this by
avoiding adding 1 to large arguments (precisely what counts as large
depends on the floating-point format).

Tested x86_64 and x86, and spot-checked log1pl tests on mips64 and
powerpc64.

	[BZ #16564]
	* sysdeps/i386/fpu/s_log1pl.S (__log1pl): Do not add 1 to positive
	arguments with exponent 65 or above.
	* sysdeps/ieee754/ldbl-128/s_log1pl.c (__log1pl): Do not add 1 to
	arguments 0x1p113L or above.
	* sysdeps/ieee754/ldbl-128ibm/s_log1pl.c (__log1pl): Do not add 1
	to arguments 0x1p107L or above.
	* sysdeps/x86_64/fpu/s_log1pl.S (__log1pl): Do not add 1 to
	positive arguments with exponent 65 or above.
	* math/auto-libm-test-in: Add more tests of log1p.
	* math/auto-libm-test-out: Regenerated.