Add libm-test support for per-rounding-mode manually specified results.

This patch continues the libm-test move towards automatic testing of
all test inputs in all rounding modes by adding gen-libm-test.pl
support for tests specifying results in each rounding mode manually.

Previously a TEST_* line could specify arguments and results, or
arguments, results and flags.  Now there is the option of (arguments,
results-rd, flags-rd, results-rn, flags-rn, results-rz, flags-rz,
results-ru, flags-ru).  This is used to replace the separate arrays of
results in each rounding mode for lrint, llrint and rint.  (In the
case of rint, some tests were only in rint_test_data and needed to
have expectations for non-default rounding modes added, which I did
manually.  In various cases there were slight differences in things
such as the ordering of tests in the arrays for each mode.)

Tested x86_64 and x86.

	* math/gen-libm-test.pl (parse_args): Handle results specified for
	each rounding mode separately.
	* math/libm-test.inc (lrint_test_data): Merge in per-rounding-mode
	tests and results from lrint_tonearest_test_data,
	lrint_towardzero_test_data, lrint_downward_test_data and
	lrint_upward_test_data.
	(lrint_test): Use ALL_RM_TEST.
	(lrint_tonearest_test_data): Remove.
	(lrint_test_tonearest): Likewise.
	(lrint_towardzero_test_data): Likewise.
	(lrint_test_towardzero): Likewise.
	(lrint_downward_test_data): Likewise.
	(lrint_test_downward): Likewise.
	(lrint_upward_test_data): Likewise.
	(lrint_test_upward): Likewise.
	(llrint_test_data): Merge in per-rounding-mode tests and results
	from llrint_tonearest_test_data, llrint_towardzero_test_data,
	llrint_downward_test_data and llrint_upward_test_data.
	(llrint_test): Use ALL_RM_TEST.
	(llrint_tonearest_test_data): Remove.
	(llrint_test_tonearest): Likewise.
	(llrint_towardzero_test_data): Likewise.
	(llrint_test_towardzero): Likewise.
	(llrint_downward_test_data): Likewise.
	(llrint_test_downward): Likewise.
	(llrint_upward_test_data): Likewise.
	(llrint_test_upward): Likewise.
	(rint_test_data): Merge in per-rounding-mode tests and results
	from rint_tonearest_test_data, rint_towardzero_test_data,
	rint_downward_test_data and rint_upward_test_data.  Add
	per-rounding-mode results for tests not in those arrays.
	(rint_test): Use ALL_RM_TEST.
	(rint_tonearest_test_data): Remove.
	(rint_test_tonearest): Likewise.
	(rint_towardzero_test_data): Likewise.
	(rint_test_towardzero): Likewise.
	(rint_downward_test_data): Likewise.
	(rint_test_downward): Likewise.
	(rint_upward_test_data): Likewise.
	(rint_test_upward): Likewise.
	(main): Don't call removed functions.