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

compiler/testData/diagnostics/tests/smartCasts/varInsideLocalFun.fir.kt

@@ -0,0 +1,17 @@
+// Based on KT-8643
+public class MyClass
+{
+    fun main() {
+        var str: String? = null
+
+        if (str != null)
+            callback {
+                // Nodoby writes str, smart cast is possible
+                method1(str)
+            }
+    }
+
+    inline fun callback(foo: () ->Unit) = foo()
+
+    fun method1(str: String) = str
+}