gh-138580: Add sys.float_info.iec_60559 boolean flag (#138811)

This value indicating support the IEC 60559 floating-point standard (the
Annex F of C99).  If enabled, the float type characteristics matches the
IEC 60559 double format and exceptional cases for the math's functions
follow to the section F.10 of the C99 standard.

Co-authored-by: Victor Stinner <vstinner@python.org>
Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>