Elements. Remove V1 LabelElement.

Change-Id: I0f6828177b227d867360fe51bc57aeb5a9d4ff42
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/423420
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: scheglov

pkg/analyzer/api.txt

@@ -3175,10 +3175,6 @@ package:analyzer/dart/element/element.dart:
     new (constructor: JoinPatternVariableElement Function())
     isConsistent (getter: bool)
     variables (getter: List<PatternVariableElement>)
-  LabelElement (class extends Object implements Element, deprecated):
-    new (constructor: LabelElement Function())
-    enclosingElement3 (getter: ExecutableElement, deprecated)
-    name (getter: String)
   LibraryElement (class extends Object implements _ExistingElement, deprecated):
     new (constructor: LibraryElement Function())
     definingCompilationUnit (getter: CompilationUnitElement, deprecated)

pkg/analyzer/lib/dart/element/element.dart

@@ -914,19 +914,6 @@ abstract class JoinPatternVariableElement implements PatternVariableElement {
   List<PatternVariableElement> get variables;
 }
 
-/// A label associated with a statement.
-///
-/// Clients may not extend, implement or mix-in this class.
-@Deprecated('Use LabelElement2 instead')
-abstract class LabelElement implements Element {
-  @Deprecated(elementModelDeprecationMsg)
-  @override
-  ExecutableElement get enclosingElement3;
-
-  @override
-  String get name;
-}
-
 /// A library.
 ///
 /// Clients may not extend, implement or mix-in this class.

pkg/analyzer/lib/src/dart/element/element.dart

@@ -6351,11 +6351,7 @@ class JoinPatternVariableElementImpl2 extends PatternVariableElementImpl2
       super._wrappedElement as JoinPatternVariableElementImpl;
 }
 
-class LabelElementImpl extends ElementImpl
-    implements
-        // ignore:deprecated_member_use_from_same_package,analyzer_use_new_elements
-        LabelElement,
-        LabelFragment {
+class LabelElementImpl extends ElementImpl implements LabelFragment {
   late final LabelElementImpl2 element2 = LabelElementImpl2(this);
 
   /// A flag indicating whether this label is associated with a `switch` member