Fix PR middle-end/107705: ICE after reclaration error

The problem here is after we created a call expression
in the C front-end, we replace the decl type with
an error mark node. We then end up calling
aggregate_value_p with the call expression
with the decl with the error mark as the type
and we ICE.

The fix is to check the function type
after we process the call expression inside
aggregate_value_p to get it.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

Thanks,
Andrew Pinski

gcc/ChangeLog:

	PR middle-end/107705
	* function.cc (aggregate_value_p): Return 0 if
	the function type was an error operand.

gcc/testsuite/ChangeLog:

	* gcc.dg/redecl-22.c: New test.