Test rint and nearbyint with same inputs, in all rounding modes.

Test rint and nearbyint with same inputs, in all rounding modes.

This patch arranges for rint and nearbyint to be tested by
libm-test.inc with the same inputs (previously each had some test
inputs the other didn't, although there was a lot of overlap as well),
and for nearbyint to be tested in all rounding modes where previously
it was only tested in round-to-nearest mode.  The expected results are
the same for each function, except that rint is expected to have
"inexact" exceptions for non-integer input and nearbyint is expected
not to have those exceptions.

Tested x86_64 and x86.

	* math/libm-test.inc (nearbyint_test_data): Include all tests used
	for rint.  Include results for all rounding modes.
	(nearbyint_test): Use ALL_RM_TEST.
	(rint_test_data): Include all tests used for nearbyint.