remainder* tests: More tests.

remainder* tests: More tests.

* tests/test-remainder.h: New file, based on tests/test-fmod.h.
* tests/test-remainder.c: Include <float.h> and test-remainder.h.
(main): Invoke test_function.
* tests/test-remainderf.c: Include <float.h> and test-remainder.h.
(main): Invoke test_function.
* tests/test-remainderl.c: Include <float.h> and test-remainder.h.
(main): Invoke test_function.
* modules/remainder-tests (Files): Add tests/test-remainder.h,
tests/randomd.c.
(Makefile.am): Add randomd.c to test_remainder_SOURCES.
* modules/remainderf-tests (Files): Add tests/test-remainder.h,
tests/randomf.c.
(Makefile.am): Add randomf.c to test_remainderf_SOURCES.
* modules/remainderl-tests (Files): Add tests/test-remainder.h,
tests/randoml.c.
(Depends-on): Add 'float'.
(Makefile.am): Add randoml.c to test_remainderl_SOURCES.