Set and test no-warning bit to avoid -Wnonnull for synthesized expressions.

Set and test no-warning bit to avoid -Wnonnull for synthesized expressions.

Resolves:
PR c++/96003 spurious -Wnonnull calling a member on the result of static_cast

gcc/c-family/ChangeLog:

	PR c++/96003
	* c-common.c (check_function_arguments_recurse): Return early when
	no-warning bit is set.

gcc/cp/ChangeLog:

	PR c++/96003
	* class.c (build_base_path): Set no-warning bit on the synthesized
	conditional expression in static_cast.

gcc/testsuite/ChangeLog:

	PR c++/96003
	* g++.dg/warn/Wnonnull7.C: New test.