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

compiler/testData/diagnostics/tests/secondaryConstructors/dataClasses.fir.kt

@@ -0,0 +1,14 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+data class A1(val x: String) {
+    constructor(): this("")
+}
+
+data class A2(val y: String, val z: Int) {
+    constructor(x: String): this(x, 0)
+}
+
+data class A3 {
+    constructor()
+}
+
+data class A4 internal constructor()