fix list_test for strong mode, and fix DDC List constructors

pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/classes.dart

Index: pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/classes.dart
diff --git a/pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/classes.dart b/pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/classes.dart
index c7b57180345c52a334056562f02a5b89a16c61ca..8c9fca76ada86710d1b8be6ec04c6d62eec81de9 100644
--- a/pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/classes.dart
+++ b/pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/classes.dart
@@ -531,12 +531,6 @@ defineExtensionMembers(type, methodNames) => JS('', '''(() => {
   upgradeSig($_setterSig);
 })()''');
 
-/// Sets the type of `obj` to be `type`
-setType(obj, type) {
-  JS('', '#.__proto__ = #.prototype', obj, type);
-  return obj;
-}
-
 /// Link the extension to the type it's extending as a base class.
 setBaseClass(derived, base) {
   JS('', '#.prototype.__proto__ = #.prototype', derived, base);