Allopen: Handle allopen annotations on classes (KT-12149)

plugins/allopen/testData/bytecodeListing/allOpenOnNotClasses.kt

@@ -0,0 +1,19 @@
+@AllOpen
+annotation class AllOpen
+
+@AllOpen
+interface Intf
+
+@AllOpen
+object Obj
+
+@AllOpen
+enum class Enum
+
+class MyClass {
+    @AllOpen
+    fun method() {}
+
+    @field:AllOpen @get:AllOpen @set:AllOpen
+    var prop: String = ""
+}