Fix profiledbootstrap poly_int fallout [PR111642]

Fix profiledbootstrap poly_int fallout [PR111642]

rtl-tests.cc and simplify-rtx.cc used partial specialisation
to try to restrict the NUM_POLY_INT_COEFFS>1 tests without
resorting to preprocessor tests.  That now triggers an error
in some configurations, since the NUM_POLY_INT_COEFFS>1 tests
used the global poly_int64, whose definition does not depend
on the template parameter.

This patch uses local types that do depend on the template parameter.

gcc/
	PR bootstrap/111642
	* rtl-tests.cc (const_poly_int_tests<N>::run): Use a local
	poly_int64 typedef.
	* simplify-rtx.cc (simplify_const_poly_int_tests<N>::run): Likewise.