Generate copy function for data classes

#KT-2779 Fixed

compiler/testData/codegen/dataClasses/copy/withGenericParameter.kt

@@ -0,0 +1,14 @@
+data class A(val a: Foo<String>) {}
+
+class Foo<T>(val a: T) { }
+
+fun box() : String {
+    val f1 = Foo("a")
+    val f2 = Foo("b")
+    val a = A(f1)
+    val b = a.copy(f2)
+    if (b.a.a == "b") {
+        return "OK"
+    }
+    return "fail"
+}