totalorder* tests: Test also the signalling NaNs. * tests/test-totalorder.h: Include signed-snan.h. (main): Change the array initializer to contain memory_* objects rather than floating-point numbers. This is needed for i386 and x86_64 CPUs. * tests/test-totalorder.c (TOTALORDER_TYPE): Use memory_double. (TOTALORDER_HAVE_SNAN, TOTALORDER_POSITIVE_SNAN, TOTALORDER_NEGATIVE_SNAN): New macros. * tests/test-totalorderf.c (TOTALORDER_TYPE): Use memory_float. (TOTALORDER_HAVE_SNAN, TOTALORDER_POSITIVE_SNAN, TOTALORDER_NEGATIVE_SNAN): New macros. * tests/test-totalorderl.c (TOTALORDER_TYPE): Use memory_long_double. (TOTALORDER_HAVE_SNAN, TOTALORDER_POSITIVE_SNAN, TOTALORDER_NEGATIVE_SNAN): New macros. * modules/totalorder-tests (Depends-on): Add signed-snan. * modules/totalorderf-tests (Depends-on): Likewise. * modules/totalorderl-tests (Depends-on): Likewise.