Make TypeConstructor.isFinal return false for enums

The reason is that before dc02b2e3ab and 8a0dcca957,
TypeConstructor.isFinal for some class descriptors
(DeserializedClassDescriptor, LazyJavaClassDescriptor,
MutableClassDescriptor) were implemented as `isFinalClass` (which is
`modality == FINAL && kind != ENUM_CLASS`), and all others as
`modality == FINAL` or simply true/false. This led to differences in
behavior depending on the exact instance of the class descriptor.
Now that TypeConstructor.isFinal is always `modality == FINAL`, some
tests (PseudoValueTestGenerated) fail because the finality of some type
constructors changed and these tests render final vs non-final type
constructors differently.

In this commit, TypeConstructor.isFinal is now made to behave safer,
i.e. considering enum class type constructor to be non-final (as was the
case earlier for some ClassDescriptor instances). Some diagnostics might
disappear (e.g. FINAL_UPPER_BOUND) but it doesn't look like a big deal

compiler/testData/cfg/declarations/classesAndObjects/EnumEntryRefersCompanion.values

@@ -10,8 +10,8 @@ enum class EE(val x: Int) {
 ---------------------
                     <v0>: Int             NEW: magic[FAKE_INITIALIZER](val x: Int) -> <v0>
                     <v10>: EE.Companion   NEW: magic[FAKE_INITIALIZER](companion object { fun foo() = 42 }) -> <v10>
-                    <v1>: EE              NEW: magic[FAKE_INITIALIZER](INSTANCE(Companion.foo()),) -> <v1>
-                    <v5>: EE              NEW: magic[FAKE_INITIALIZER](ANOTHER(foo());) -> <v5>
+                    <v1>: {<: EE}         NEW: magic[FAKE_INITIALIZER](INSTANCE(Companion.foo()),) -> <v1>
+                    <v5>: {<: EE}         NEW: magic[FAKE_INITIALIZER](ANOTHER(foo());) -> <v5>
                     <v7>: EE.Companion    NEW: magic[IMPLICIT_RECEIVER](foo()) -> <v7>
 Companion           <v2>: EE.Companion    NEW: r(Companion) -> <v2>
 foo()               <v3>: Int             NEW: call(foo(), foo|<v2>) -> <v3>