Introduce ClassKind#CLASS_OBJECT and ClassKind#isObject and usages.

Rename LazyClassDescriptor#onlyEnumEntries -> enumClassObjectInfo.
Determine ClassKind in JetClassInfo and JetObjectInfo constructor.
Remove complex constructor for enum entry in enum test.
Logic simplified in LazyClassMemberScope.
Minor refactorings.

compiler/testData/lazyResolve/descriptorRenderer/ClassObject.kt

@@ -4,4 +4,4 @@ trait TheTrait {
 }
 
 //internal trait TheTrait defined in root package
-//object defined in TheTrait
+//class object defined in TheTrait

compiler/testData/lazyResolve/namespaceComparator/enum.kt

@@ -2,6 +2,5 @@ package test
 
 enum class Test(a : Int) {
   A : Test(0)
-  B(x : Int) : Test(x)
-  C : Test(0) {}
+  B : Test(0) {}
 }

compiler/testData/lazyResolve/namespaceComparator/enum.txt

@@ -7,19 +7,14 @@ internal final enum class test.Test : jet.Enum<test.Test> {
     internal final class object test.Test.<class-object-for-Test> {
         internal final /*constructor*/ fun <init>(): test.Test.<class-object-for-Test>
         internal final val A: test.Test.<class-object-for-Test>.A
-        internal final val C: test.Test.<class-object-for-Test>.C
+        internal final val B: test.Test.<class-object-for-Test>.B
         internal final enum entry test.Test.<class-object-for-Test>.A : test.Test {
             internal final /*constructor*/ fun <init>(): test.Test.<class-object-for-Test>.A
             public final override /*1*/ fun name(): jet.String
             public final override /*1*/ fun ordinal(): jet.Int
         }
         internal final enum entry test.Test.<class-object-for-Test>.B : test.Test {
-            public final /*constructor*/ fun <init>(/*0*/ x: jet.Int): test.Test.<class-object-for-Test>.B
-            public final override /*1*/ fun name(): jet.String
-            public final override /*1*/ fun ordinal(): jet.Int
-        }
-        internal final enum entry test.Test.<class-object-for-Test>.C : test.Test {
-            internal final /*constructor*/ fun <init>(): test.Test.<class-object-for-Test>.C
+            internal final /*constructor*/ fun <init>(): test.Test.<class-object-for-Test>.B
             public final override /*1*/ fun name(): jet.String
             public final override /*1*/ fun ordinal(): jet.Int
         }

compiler/testData/renderer/Classes.kt

@@ -37,5 +37,5 @@ trait TheTrait {
 //internal final class InternalClass defined in rendererTest
 //internal trait TheTrait defined in rendererTest
 //internal abstract fun abstractFun() : Unit defined in rendererTest.TheTrait
-//object : rendererTest.TheClass<jet.Int, jet.Int> defined in rendererTest.TheTrait
+//class object : rendererTest.TheClass<jet.Int, jet.Int> defined in rendererTest.TheTrait
 //internal final fun classObjectFunction() : jet.Int defined in rendererTest.TheTrait.<class-object-for-TheTrait>