Migrate first block of tests in standalone to standalone_2

tests/standalone/fragmentation_test.dart

-// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
-// 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.
-
-// Deliberately fragment the heap and test that GC peformance does not
-// break down.  See https://github.com/dart-lang/sdk/issues/29588
-// Normally runs in about 6-7 seconds on an x64 machine, using about 2.5Gbytes
-// of memory.
-//
-// This test is deliberately CPU-light and so it can make a lot of
-// progress before the concurrent sweepers are done sweeping the heap.
-// In that time there is no freelist and so the issue does not arise.
-// VMOptions=--no-concurrent-sweep
-
-main() {
-  final List<List> arrays = [];
-  // Fill up heap with alternate large-small items.
-  for (int i = 0; i < 500000; i++) {
-    arrays.add(new List(260));
-    arrays.add(new List(1));
-  }
-  // Clear the large items so that the heap is full of 260-word gaps.
-  for (int i = 0; i < arrays.length; i += 2) {
-    arrays[i] = null;
-  }
-  // Allocate a lot of 300-word objects that don't fit in the gaps.
-  for (int i = 0; i < 600000; i++) {
-    arrays.add(new List(300));
-  }
-}