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

compiler/testData/diagnostics/tests/generics/innerClasses/iterator.fir.kt

@@ -0,0 +1,37 @@
+// !WITH_NEW_INFERENCE
+// !CHECK_TYPE
+// !DIAGNOSTICS: -ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE -UNUSED_VALUE -UNUSED_PARAMETER -UNUSED_VARIABLE
+// JAVAC_EXPECTED_FILE
+import java.util.*
+
+class A<T> : AbstractCollection<T>() {
+    override fun iterator(): MyIt = MyIt()
+
+    override val size: Int
+        get() = 1
+
+    inner class MyIt : MutableIterator<T> {
+        override fun next(): T {
+            throw UnsupportedOperationException()
+        }
+
+        override fun hasNext(): Boolean {
+            throw UnsupportedOperationException()
+        }
+
+        override fun remove() {
+            throw UnsupportedOperationException()
+        }
+    }
+}
+
+fun <E> commonSupertype(x: E, y: E): E = x
+
+fun foo() {
+    var myIt = A<String>().iterator()
+    myIt = A<Int>().iterator()
+
+    val csIt: Iterator<CharSequence> = A<String>().iterator()
+
+    commonSupertype(A<String>().iterator(), A<Int>().iterator()).checkType { _<A<out Any>.MyIt>() }
+}