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

compiler/testData/diagnostics/tests/when/EmptyConditionWithExpressionEnum.fir.kt

@@ -0,0 +1,9 @@
+// EA-68871: empty when condition
+enum class My { FIRST, SECOND }
+fun foo(arg: My): Int {
+    when (arg) {
+        My.FIRST -> return 0
+        <!SYNTAX!><!>-> return 4
+        else -> return -1
+    }
+}