[Telemetry] Fix page_cycler benchmark on machines in positive timezones.

The creation date in GetChildPids is in the form <date>[-+]<timezone>. The
old code only handled negative timezones. This updates it to handle both.

BUG=232254
TEST=morejs page cycler on windows with timezone set to israel
NOTRY=True

Review URL: https://codereview.chromium.org/14328005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@194686 0039d316-1c4b-4281-b951-d872f2087c98

tools/telemetry/telemetry/core/chrome/win_platform_backend.py

@@ -4,6 +4,7 @@
 
 import collections
 import ctypes
+import re
 import subprocess
 try:
   import pywintypes  # pylint: disable=F0401
@@ -113,7 +114,7 @@ class WinPlatformBackend(platform_backend.PlatformBackend):
       _, creation, curr_ppid, curr_pid = creation_ppid_pid.split(',')
       ppid_map[int(curr_ppid)].append(int(curr_pid))
       if creation:
-        creation_map[int(curr_pid)] = float(creation.split('-')[0])
+        creation_map[int(curr_pid)] = float(re.split('[+-]', creation)[0])
 
     def _InnerGetChildPids(pid):
       if not pid or pid not in ppid_map: