[ddc] Delete unnecessary super invocations

There are no overrides of these methods so calling with `super.`
is just confusing and error prone.

Change-Id: Iae2081b733d7917eefe48827e50c42b58704667a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/376022
Commit-Queue: Mark Zhou <markzipan@google.com>
Auto-Submit: Nicholas Shahan <nshahan@google.com>
Reviewed-by: Mark Zhou <markzipan@google.com>
diff --git a/pkg/dev_compiler/lib/src/kernel/compiler.dart b/pkg/dev_compiler/lib/src/kernel/compiler.dart
index 6ff8c0f..8ccb39a 100644
--- a/pkg/dev_compiler/lib/src/kernel/compiler.dart
+++ b/pkg/dev_compiler/lib/src/kernel/compiler.dart
@@ -3379,13 +3379,13 @@
 
     // TODO(jmesserly): need a way of determining if parameters are
     // potentially mutated in Kernel. For now we assume all parameters are.
-    super.enterFunction(name, formals, () => true);
+    enterFunction(name, formals, () => true);
 
     var block = isSync
         ? _emitSyncFunctionBody(f, name)
         : _emitGeneratorFunctionBody(f, name);
 
-    block = super.exitFunction(formals, block);
+    block = exitFunction(formals, block);
     _currentTypeEnvironment = savedTypeEnvironment;
     return js_ast.Fun(formals, block);
   }
@@ -4613,7 +4613,7 @@
   js_ast.Statement visitReturnStatement(ReturnStatement node) {
     var expression = node.expression;
     var value = expression == null ? null : _visitExpression(expression);
-    return super.emitReturnStatement(value);
+    return emitReturnStatement(value);
   }
 
   @override