Remove unneeded `strong_mode_down_cast_composite` ignores.

pkg/analyzer/tool/summary/mini_ast.dart

Index: pkg/analyzer/tool/summary/mini_ast.dart
diff --git a/pkg/analyzer/tool/summary/mini_ast.dart b/pkg/analyzer/tool/summary/mini_ast.dart
index 3d6a09a73f5058c28e78dae69be63fbaaa9ed371..7aa9433627ba9842074eca71bdff474454987ce1 100644
--- a/pkg/analyzer/tool/summary/mini_ast.dart
+++ b/pkg/analyzer/tool/summary/mini_ast.dart
@@ -189,12 +189,10 @@ class MiniAstBuilder extends StackListener {
       Token implementsKeyword,
       Token endToken) {
     debugEvent("ClassDeclaration");
-    // ignore: strong_mode_down_cast_composite
     List<ClassMember> members = pop();
     TypeName superclass = pop();
     pop(); // Type variables
     String name = pop();
-    // ignore: strong_mode_down_cast_composite
     List<Annotation> metadata = pop();
     Comment comment = pop();
     compilationUnit.declarations.add(
@@ -226,10 +224,8 @@ class MiniAstBuilder extends StackListener {
 
   void endEnum(Token enumKeyword, Token endBrace, int count) {
     debugEvent("Enum");
-    // ignore: strong_mode_down_cast_composite
     List<EnumConstantDeclaration> constants = popList(count);
     String name = pop();
-    // ignore: strong_mode_down_cast_composite
     List<Annotation> metadata = pop();
     Comment comment = pop();
     compilationUnit.declarations
@@ -242,7 +238,6 @@ class MiniAstBuilder extends StackListener {
     debugEvent("FactoryMethod");
     pop(); // Body
     ConstructorReference name = pop();
-    // ignore: strong_mode_down_cast_composite
     List<Annotation> metadata = pop();
     Comment comment = pop();
     push(new ConstructorDeclaration(comment, metadata, name));
@@ -309,7 +304,6 @@ class MiniAstBuilder extends StackListener {
   void endMetadata(Token beginToken, Token periodBeforeName, Token endToken) {
     debugEvent("Metadata");
     inMetadata = false;
-    // ignore: strong_mode_down_cast_composite
     List<Expression> arguments = pop();
     String constructorName = popIfNotNull(periodBeforeName);
     pop(); // Type arguments
@@ -331,7 +325,6 @@ class MiniAstBuilder extends StackListener {
     pop(); // Type variables
     String name = pop();
     TypeName returnType = pop();
-    // ignore: strong_mode_down_cast_composite
     List<Annotation> metadata = pop();
     Comment comment = pop();
     push(new MethodDeclaration(
@@ -341,7 +334,6 @@ class MiniAstBuilder extends StackListener {
   @override
   void endSend(Token beginToken, Token endToken) {
     debugEvent("Send");
-    // ignore: strong_mode_down_cast_composite
     pop(); // Arguments
     pop(); // Type arguments
     pop(); // Receiver
@@ -435,7 +427,6 @@ class MiniAstBuilder extends StackListener {
   @override
   void handleType(Token beginToken, Token endToken) {
     debugEvent("Type");
-    // ignore: strong_mode_down_cast_composite
     List<TypeName> typeArguments = pop();
     String name = pop();
     push(new TypeName(name, typeArguments));