FIR2IR: store and convert annotations on enum entry

compiler/testData/ir/irText/declarations/annotations/enumEntriesWithAnnotations.fir.txt

@@ -35,9 +35,13 @@ FILE fqName:<root> fileName:/enumEntriesWithAnnotations.kt
           <E>: <root>.TestEnum
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS ENUM_CLASS name:TestEnum modality:OPEN visibility:public superTypes:[kotlin.Enum<<root>.TestEnum>]'
     ENUM_ENTRY name:ENTRY1
+      annotations:
+        TestAnn(x = 'ENTRY1')
       init: EXPRESSION_BODY
         ENUM_CONSTRUCTOR_CALL 'private constructor <init> () [primary] declared in <root>.TestEnum'
     ENUM_ENTRY name:ENTRY2
+      annotations:
+        TestAnn(x = 'ENTRY2')
       init: EXPRESSION_BODY
         ENUM_CONSTRUCTOR_CALL 'private constructor <init> () [primary] declared in <root>.TestEnum.ENTRY2'
       class: CLASS ENUM_ENTRY name:ENTRY2 modality:FINAL visibility:private superTypes:[<root>.TestEnum]