IBM Z: Fix ICE with overloading and checking enabled

IBM Z: Fix ICE with overloading and checking enabled

s390_resolve_overloaded_builtin, when called on NON_DEPENDENT_EXPR,
ICEs when using the type from it which ends up as error_mark_node.

This particular instance of the problem does not occur anymore since
NON_DEPENDENT_EXPR has been removed.  Nevertheless that case needs to
be handled here.

gcc/ChangeLog:

	* config/s390/s390-c.cc (s390_fn_types_compatible): Add a check
	for error_mark_node.

gcc/testsuite/ChangeLog:

	* g++.target/s390/zvec-templ-1.C: New test.