JetDiagnosticsTest migrated to TestGenerator

- test data files renamed from *.jet to *.kt

compiler/testData/diagnostics/tests/operatorsOverloading/kt1028.kt

@@ -0,0 +1,35 @@
+//KT-1028 Wrong type checking for plusAssign
+package kt1028
+
+import java.util.*
+
+class event<T>()
+{
+    val callbacks = ArrayList< Function1<T, Unit> >() // Should be ArrayList<()->Unit>, bug posted
+
+    fun plusAssign(f : (T) -> Unit) = callbacks.add(f)
+    fun minusAssign(f : (T) -> Unit) = callbacks.remove(f)
+    fun call(value : T) = for(c in callbacks) c(value)
+}
+
+class MouseMovedEventArgs()
+{
+    public val X : Int = 0
+}
+
+class Control()
+{
+    public val MouseMoved : event<MouseMovedEventArgs> = event<MouseMovedEventArgs>()
+
+    fun MoveMouse() = MouseMoved.call(MouseMovedEventArgs())
+}
+
+class Test()
+{
+    fun test()
+    {
+        val control = Control()
+        control.MouseMoved <!ASSIGNMENT_OPERATOR_SHOULD_RETURN_UNIT!>+=<!> { it.X } // here
+        control.MouseMoved.plusAssign( { it.X } ) // ok
+    }
+}