[Telemetry] Enable the sandbox for page cyclers on Windows.

Everything seems to run fine locally.

BUG=270920

Review URL: https://codereview.chromium.org/513543007

Cr-Commit-Position: refs/heads/master@{#292714}

tools/perf/metrics/iometric.py

@@ -14,7 +14,7 @@ class IOMetric(Metric):
   @classmethod
   def CustomizeBrowserOptions(cls, options):
     # TODO(tonyg): This is the host platform, so not totally correct.
-    if sys.platform != 'darwin':
+    if sys.platform not in ('darwin', 'win32'):
       # TODO(playmobil): Get rid of this on all platforms crbug.com/361049.
       options.AppendExtraBrowserArgs('--no-sandbox')