ldexp, ldexpf, ldexpl: Enhance tests.

ldexp, ldexpf, ldexpl: Enhance tests.

* tests/test-ldexp.h: New file, combining code from tests/test-ldexp.c
and tests/test-ldexpl.c.
* tests/test-ldexpl.c: (DOUBLE, ISNAN, INFINITY, NAN, L_, MINUS_ZERO,
LDEXP, MIN_EXP, MAX_EXP): New macros.
Include test-ldexp.h.
(main): Just call test_function.
* tests/test-ldexp.c: Include float.h, isnand-nolibm.h, minus-zero.h,
infinity.h, nan.h.
(DOUBLE, ISNAN, INFINITY, NAN, L_, MINUS_ZERO, LDEXP, MIN_EXP,
MAX_EXP): New macros.
Include test-ldexp.h.
(x, y): Remove variables.
(main): Just call test_function.
* tests/test-ldexpf.c: Include float.h, isnanf-nolibm.h, minus-zero.h,
infinity.h, nan.h.
(DOUBLE, ISNAN, INFINITY, NAN, L_, MINUS_ZERO, LDEXP, MIN_EXP,
MAX_EXP): New macros.
Include test-ldexp.h.
(x, y): Remove variables.
(main): Just call test_function.
* modules/ldexpl-tests (Files): Add tests/test-ldexp.h.
* modules/ldexp-tests (Files): Add tests/test-ldexp.h,
tests/minus-zero.h, tests/infinity.h, tests/nan.h.
(Depends-on): Add isnand-nolibm, signbit, float.
* modules/ldexpf-tests (Files): Add tests/test-ldexp.h,
tests/minus-zero.h, tests/infinity.h, tests/nan.h.
(Depends-on): Add isnanf-nolibm, signbit, float.