modf* tests: More tests.

modf* tests: More tests.

* tests/test-modf.h: New file.
* tests/test-modf.c: Include <float.h> and test-modf.h.
(main): Invoke test_function.
* tests/test-modff.c: Include <float.h> and test-modf.h.
(main): Invoke test_function.
* tests/test-modfl.c: Include <float.h> and test-modf.h.
(main): Invoke test_function.
* modules/modf-tests (Files): Add tests/test-modf.h, tests/randomd.c.
(Makefile.am): Add randomd.c to test_modf_SOURCES.
* modules/modff-tests (Files): Add tests/test-modf.h, tests/randomf.c.
(Makefile.am): Add randomf.c to test_modff_SOURCES.
* modules/modfl-tests (Files): Add tests/test-modf.h, tests/randoml.c.
(Depends-on): Add 'float'.
(Makefile.am): Add randoml.c to test_modfl_SOURCES.