math: regenerate all math tests

math: regenerate all math tests

gen used exp range limitation to get ieee semantics but
mpfr seems to have problems with it (eg gamma(next(-180))
incorrectly underflows) so different strategy is used:
use full exp range and only narrow it before converting
the result

now the error term uses nearest rounding and sign difference
is treated as inf ulp error during tests

added helper tools to convert between float formats