JetDiagnosticsTest migrated to TestGenerator

- test data files renamed from *.jet to *.kt

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

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