Add test for obsolete issue

#KT-9571 Obsolete

compiler/testData/diagnostics/tests/generics/projectionsScope/iterateOnExtension.kt

@@ -0,0 +1,11 @@
+class A<T>
+fun <T> A<T>.foo(): Collection<T> = null!!
+
+fun main(a: A<*>, a1: A<out CharSequence>) {
+    // see KT-9571
+    for (i in a.foo()) { }
+    for (i: Any? in a.foo()) { }
+
+    for (i in a1.foo()) { }
+    for (i: CharSequence in a1.foo()) { }
+}

compiler/testData/diagnostics/tests/generics/projectionsScope/iterateOnExtension.txt

@@ -0,0 +1,11 @@
+package
+
+public fun main(/*0*/ a: A<*>, /*1*/ a1: A<out kotlin.CharSequence>): kotlin.Unit
+public fun </*0*/ T> A<T>.foo(): kotlin.collections.Collection<T>
+
+public final class A</*0*/ T> {
+    public constructor A</*0*/ T>()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}