Add further tests of libm functions.

Add further tests of libm functions.

This patch adds more randomly-generated tests of various libm
functions that are observed to increase ulps on x86_64.  (This process
must eventually converge, when my random test generation stops finding
inputs that increase the listed ulps, except maybe for any cases
uncovered where the errors exceed the maximum allowed 9ulp error and
so indicate actual libm bugs needing fixing.)

Tested for x86_64 and x86 and ulps updated accordingly.

	* math/auto-libm-test-in: Add more tests of acosh, atanh, clog,
	clog10, csqrt, erfc, exp2, expm1, log10, log2 and sinh.
	* math/auto-libm-test-out: Regenerated.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.