Another ICE after conflicting types of redeclaration [PR109619]

Another ICE after conflicting types of redeclaration [PR109619]

This another one of these ICE after error issues with the
gimplifier and a fallout from r12-3278-g823685221de986af.
This case happens when we are trying to fold memcpy/memmove.
There is already code to try to catch ERROR_MARKs as arguments
to the builtins so just need to change them to use error_operand_p
which checks the type of the expression to see if it was an error mark
also.

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

gcc/ChangeLog:

	PR c/109619
	* builtins.cc (fold_builtin_1): Use error_operand_p
	instead of checking against ERROR_MARK.
	(fold_builtin_2): Likewise.
	(fold_builtin_3): Likewise.

gcc/testsuite/ChangeLog:

	PR c/109619
	* gcc.dg/redecl-26.c: New test.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>