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

compiler/testData/diagnostics/tests/regressions/Jet72.fir.kt

@@ -0,0 +1,18 @@
+// JET-72 Type inference doesn't work when iterating over ArrayList
+
+import java.util.ArrayList
+
+abstract class Item(val room: Object) {
+   abstract val name : String
+}
+
+val items: ArrayList<Item> = ArrayList<Item>()
+
+fun test(room : Object) {
+  for(item: Item? in items) {
+    if (item?.room === room) {
+      // item?.room is not null
+      System.out.println("You see " + item?.name)
+    }
+  }
+}