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

compiler/testData/diagnostics/tests/callableReference/resolve/kt12338.fir.kt

@@ -0,0 +1,9 @@
+// KT-12338 Compiler error ERROR: Rewrite at slice LEXICAL_SCOPE key: REFERENCE_EXPRESSION with when and function references
+
+fun a() { }
+
+fun test() {
+    when {
+        true -> ::a
+    }
+}