New J2K: Move nullability analysis tests to nullabilityAnalysis dir

nj2k/testData/nullabilityAnalysis/superMethod.kt

@@ -0,0 +1,12 @@
+open class A () {
+    open fun foo(x: Int): Int {
+        if (x == null);
+        return null
+    }
+}
+
+class B : A() {
+    override fun foo(x: Int): Int {
+        return 1
+    }
+}