totalorder* tests: Strengthen tests. * tests/test-totalorder.h: Include <math.h>. (positive_NaN_with_payload, negative_NaN_with_payload): New functions. (main): Test quiet NaNs of each sign with different payload. * tests/test-totalorder.c (TOTALORDER_POSITIVE_NAN, TOTALORDER_NEGATIVE_NAN): Remove macros. (TOTALORDER_SETPAYLOAD): New macro. * tests/test-totalorderf.c (TOTALORDER_POSITIVE_NAN, TOTALORDER_NEGATIVE_NAN): Remove macros. (TOTALORDER_SETPAYLOAD): New macro. * tests/test-totalorderl.c (TOTALORDER_POSITIVE_NAN, TOTALORDER_NEGATIVE_NAN): Remove macros. (TOTALORDER_SETPAYLOAD): New macro. * modules/totalorder-tests (Depends-on): Add setpayload. (Makefile.am): Link test-totalorder with $(SETPAYLOAD_LIBM). * modules/totalorderf-tests (Depends-on): Add setpayloadf. (Makefile.am): Link test-totalorderf with $(SETPAYLOADF_LIBM). * modules/totalorderl-tests (Depends-on): Add setpayloadl. (Makefile.am): Link test-totalorderl with $(SETPAYLOADL_LIBM).