re PR sanitizer/59437 (ICE in for g++ -S -fvtable-verify=std -fsanitize=null)

	PR sanitizer/59437
	* vtable-verify.c (var_is_used_for_virtual_call_p): Check the
	return value of gimple_call_fn.  Use is_gimple_call/is_gimple_assign
	instead of gimple_code.
testsuite/
	* g++.dg/ubsan/pr59437.C: New test.

From-SVN: r205854