KT-9883 prohibit using spread operator for nullable value

#KT-9883 Fixed

compiler/testData/codegen/boxWithJava/varargs/A.java

@@ -0,0 +1,7 @@
+public class A {
+    public int foo(int x, String ... args) {
+        return x + args.length;
+    }
+
+    public static String[] ar = new String[] { "a", "b"};
+}