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

compiler/visualizer/testData/rawBuilder/expressions/modifications.kt

@@ -0,0 +1,44 @@
+fun simple() {
+//      Int Int
+//      │   │
+    var x = 10
+//  var simple.x: Int
+//  │ fun (Int).plus(Int): Int
+//  │ │  Int
+//  │ │  │
+    x += 20
+//  var simple.x: Int
+//  │ fun (Int).minus(Int): Int
+//  │ │  Int
+//  │ │  │
+    x -= 5
+//  var simple.x: Int
+//  │ fun (Int).div(Int): Int
+//  │ │  Int
+//  │ │  │
+    x /= 5
+//  var simple.x: Int
+//  │ fun (Int).times(Int): Int
+//  │ │  Int
+//  │ │  │
+    x *= 10
+}
+
+//  collections/List<String>
+//  │
+fun List<String>.modify() {
+//       fun <T> collections/Collection<String>.plus(String): collections/List<String>
+//       │
+    this += "Alpha"
+//       fun <T> collections/Collection<String>.plus(String): collections/List<String>
+//       │
+    this += "Omega"
+}
+
+fun Any.modify() {
+//           collections/List<Int>
+//           │          fun <T> collections/Collection<Int>.plus(Int): collections/List<Int>
+//           │          │  Int
+//           │          │  │
+    (this as List<Int>) += 42
+}