Implement lateinit in backend

compiler/testData/codegen/box/properties/lateinit/overrideException.kt

@@ -0,0 +1,21 @@
+interface Intf {
+    val str: String
+}
+
+class A : Intf {
+    override lateinit var str: String
+
+    fun getMyStr(): String {
+        try {
+            val a = str
+        } catch (e: NullPointerException) {
+            return "OK"
+        }
+        return "FAIL"
+    }
+}
+
+fun box(): String {
+    val a = A()
+    return a.getMyStr()
+}