[Swarming] Isolate valgrind runner.

tools/run-valgrind.isolate

+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+{
+  'variables': {
+    'command': [
+      'run-valgrind.py',
+    ],
+    'files': [
+      'run-valgrind.py',
+    ],
+  },
+  'conditions': [
+    ['has_valgrind==1', {
+      'variables': {
+        'files': [
+          # This assumes vagrind binaries have been fetched as a custom deps
+          # into v8/third_party/valgrind. It is not clear on which target
+          # machine this will run, but grabbing both is cheap.
+          '../third_party/valgrind/linux_x86/',
+          '../third_party/valgrind/linux_x64/',
+        ],
+      },
+    }],
+  ],
+  'includes': [
+    '../src/d8.isolate',
+  ],
+}