Reland "Merge more Kernel infrastructure from kernel_sdk SDK fork."

runtime/lib/collection_patch.dart

Index: runtime/lib/collection_patch.dart
diff --git a/runtime/lib/collection_patch.dart b/runtime/lib/collection_patch.dart
index ed76535fc7f156453cdde7fd9223c714841ced6f..0dea1458f3e2d7ec0de0596f3cf5ad6010210077 100644
--- a/runtime/lib/collection_patch.dart
+++ b/runtime/lib/collection_patch.dart
@@ -2,10 +2,13 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:typed_data';
+import 'dart:_internal' as internal;
+
 @patch class HashMap<K, V> {
   @patch factory HashMap({ bool equals(K key1, K key2),
-                                 int hashCode(K key),
-                                 bool isValidKey(potentialKey) }) {
+                           int hashCode(K key),
+                           bool isValidKey(potentialKey) }) {
     if (isValidKey == null) {
       if (hashCode == null) {
         if (equals == null) {