hypot* tests: More tests.

hypot* tests: More tests.

* tests/test-hypot.h: New file, partially extracted from
tests/test-hypotl.c.
* tests/test-hypot.c: Include test-hypot.h.
(main): Invoke test_function.
* tests/test-hypotf.c: Include test-hypot.h.
(main): Invoke test_function.
* tests/test-hypotl.c: Include fpucw.h and test-hypot.h.
(main): Invoke BEGIN_LONG_DOUBLE_ROUNDING and test_function.
* modules/hypot-tests (Files): Add tests/test-hypot.h, tests/randomd.c.
(Makefile.am): Add randomd.c to test_hypot_SOURCES.
* modules/hypotf-tests (Files): Add tests/test-hypot.h,
tests/randomf.c.
(Makefile.am): Add randomf.c to test_hypotf_SOURCES.
* modules/hypotl-tests (Files): Add tests/test-hypot.h,
tests/randoml.c.
(Depends-on): Add 'fpucw', 'float'.
(Makefile.am): Add randoml.c to test_hypotl_SOURCES.