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

compiler/testData/diagnostics/tests/smartCasts/varnotnull/varCapturedInSafeClosure.fir.kt

@@ -0,0 +1,15 @@
+public fun foo() {
+    var s: String? = ""
+    fun closure(): Int {
+        if (s == null) {
+            return -1
+        } else {
+            return 0
+        }
+    }
+    if (s != null) {
+        System.out.println(closure())
+        // Smart cast is possible, nobody modifies s
+        System.out.println(s.length)
+    }
+}