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

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt897.fir.kt

@@ -0,0 +1,20 @@
+//KT-897 Don't allow assignment to a property before it is defined
+
+package kt897
+
+class A() {
+    init {
+        i = 11
+    }
+    val i : Int? = null // must be an error
+
+    init {
+        j = 1
+    }
+    var j : Int = 2
+
+    init {
+        k = 3
+    }
+    val k : Int
+}