Add test methods and data base on raw fir builder test data

compiler/visualizer/testData/rawBuilder/declarations/expectActual.kt

@@ -0,0 +1,15 @@
+expect class MyClass
+
+expect fun foo(): String
+
+//         Int
+//         │
+expect val x: Int
+
+actual class MyClass
+
+actual fun foo() = "Hello"
+
+//         Int Int
+//         │   │
+actual val x = 42