intprop-tests: port to older and more-pedantic compilers

intprop-tests: port to older and more-pedantic compilers

* modules/intprops-tests (Files): Add tests/macros.h.
* tests/test-intprops.c: Include macros.h.
(TYPE_IS_INTEGER): Use ASSERT, not verify, to test this macro, as
it's no longer documented to expand to an integer constant expression.
(TYPE_SIGNED): Use ASSERT, not verify, to test this macro when the
argument is floating point, as it's no longer documented to expand
to an integer constant expression in that case.
(UINT_MAX, ULONG_MAX, UINTMAX_MAX): Redefine to work around
compiler bugs reported by Bruno Haible.  See
<http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00401.html>.
(U0, U1): New constants, to work around the same bugs.  Also,
in tests, use e.g., "(unsigned int) 39" rather than "39u".