Unify handling of flags (thanks @smarter)

Author: liufengyun

compiler/src/dotty/tools/dotc/core/classfile/ClassfileConstants.scala

@@ -343,6 +343,7 @@ object ClassfileConstants {
       case JAVA_ACC_FINAL      => Final
       case JAVA_ACC_SYNTHETIC  => Synthetic
       case JAVA_ACC_STATIC     => JavaStatic
+      case JAVA_ACC_ENUM       => Enum
       case JAVA_ACC_ABSTRACT   => if (isClass) Abstract else Deferred
       case JAVA_ACC_INTERFACE  => PureInterfaceCreationFlags | JavaDefined
       case _                   => EmptyFlags

compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala

@@ -204,9 +204,6 @@ class ClassfileParser(
     if (isEnum) {
       instanceScope.toList.map(_.ensureCompleted())
       staticScope.toList.map(_.ensureCompleted())
-      val flag = if moduleRoot.is(Flags.JavaDefined) then Flags.JavaEnumTrait else Flags.Enum
-      classRoot.setFlag(flag)
-      moduleRoot.setFlag(flag)
     }
 
     result