[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/extensions/GenericIterator2.fir.kt

@@ -0,0 +1,15 @@
+// !CHECK_TYPE
+
+import java.util.Enumeration
+
+operator fun <T> java.util.Enumeration<T>.iterator() = object : Iterator<T> {
+  public override fun hasNext(): Boolean = hasMoreElements()
+
+  public override fun next() = nextElement()
+}
+
+fun a(e : java.util.Enumeration<Int>) {
+    for (i in e) {
+        <!INAPPLICABLE_CANDIDATE!>checkSubtype<!><Int>(i)
+    }
+}