Remove DDC custom error list now that strong mode analyzer handles it

test/codegen_expected/unittest/unittest.js

 dart_library.library('unittest', null, /* Imports */[
   'dart_sdk',
   'stack_trace'
 ], function load__unittest(exports, dart_sdk, stack_trace) {
   'use strict';
   const core = dart_sdk.core;
   const collection = dart_sdk.collection;
   const async = dart_sdk.async;
   const _interceptors = dart_sdk._interceptors;
   const isolate = dart_sdk.isolate;
@@ skipping 2179 matching lines @@
         } else {
           return dart.str`${src__matcher__pretty_print._typeName(object)}:${value}`;
         }
       }
     }
     dart.fn(_prettyPrint, dynamicAndintAndSet__ToString());
     return _prettyPrint(object, 0, core.Set.new(), true);
   };
   dart.fn(src__matcher__pretty_print.prettyPrint, dynamic__ToString());
   src__matcher__pretty_print._indent = function(length) {
-    return core.List.filled(length, ' ')[dartx.join]('');
+    return ListOfString().filled(length, ' ')[dartx.join]('');
   };
   dart.fn(src__matcher__pretty_print._indent, intToString());
   src__matcher__pretty_print._typeName = function(x) {
     try {
       if (x == null) return "null";
       let type = dart.toString(dart.runtimeType(x));
       return dart.test(type[dartx.startsWith]("_")) ? "?" : type;
     } catch (e) {
       return "?";
     }
@@ skipping 1520 matching lines @@
   exports.src__internal_test_case = src__internal_test_case;
   exports.src__test_environment = src__test_environment;
   exports.src__group_context = src__group_context;
   exports.src__utils = src__utils;
   exports.src__test_case = src__test_case;
   exports.src__expected_function = src__expected_function;
   exports.html_config = html_config;
   exports.html_individual_config = html_individual_config;
   exports.html_enhanced_config = html_enhanced_config;
 });