Fix for KT-14597: "When" over smartcasted enum is broken and breaks all other "when"

#KT-14597 Fixed

compiler/testData/codegen/light-analysis/when/enumOptimization/kt14597.txt

@@ -0,0 +1,14 @@
+@kotlin.Metadata
+public enum class En {
+    public final static field A: En
+    public final static field B: En
+    public final static field С: En
+    protected method <init>(p0: java.lang.String, p1: int): void
+    public static method valueOf(p0: java.lang.String): En
+    public static method values(): En[]
+}
+
+@kotlin.Metadata
+public final class Kt14597Kt {
+    public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
+}