[Telemetry] Set the number of processes to use for telemetry_unittests on win platform to be 1

chrome/telemetry_unittests.isolate

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 {
   'includes': [
     '../tools/perf/chrome_telemetry_build/telemetry_chrome_test.isolate',
   ],
   'conditions': [
     ['OS=="mac" or OS=="win"', {
       'variables': {
         'files': [
           # Other dependencies of the tests and their harness.
           '../testing/test_env.py',
           '../testing/xvfb.py',
           '../testing/scripts/common.py',
           '../testing/scripts/run_telemetry_as_googletest.py',
         ],
+      }
+    }],
+    ['OS=="mac"', {
+      'variables': {
         'command': [
           '../testing/scripts/run_telemetry_as_googletest.py',
           '../tools/telemetry/run_tests',
           '-v',
           '--chrome-root',
-          '..'
+          '..',
         ],
       },
     }],
+    ['OS=="win"', {
+      'variables': {
+        'command': [
+          '../testing/scripts/run_telemetry_as_googletest.py',
+          '../tools/telemetry/run_tests',
+          '-v',
+          '--chrome-root',
+          '..',
+          # crbug.com/559154
+          # TODO(nednguyen): Remove --jobs=1 once the bug is fixed to speed up
+          # the test run.
+          '--job=1',
+        ],
+      },
+    }],
   ]
 }