floorl-ieee tests: More tests. * tests/test-floorl-ieee.c: Include isnanl-nolibm.h, infinity.h, nan.h. (main): Add tests for [MX] shaded specification in POSIX. * modules/floorl-ieee-tests (Files): Add tests/infinity.h, tests/nan.h. (Depends-on): Add isnanl-nolibm.