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

compiler/testData/diagnostics/tests/cast/ExtensionAsNonExtension.fir.kt

@@ -0,0 +1,10 @@
+fun f(a: (Int) -> Unit) {
+    a as Int.() -> Unit
+
+    f1(a as Int.() -> Unit)
+}
+
+fun f1(a: Int.() -> Unit) {
+    a as (Int) -> Unit
+    f(a as (Int) -> Unit)
+}