[tools/perf] Disable long running gmail tests on Android

Stories are flaking with occasional WPR redirect errors.

Bug: 726301
Change-Id: I6df1767a4a069dc9a76c4f56432f21f04c9516ce
Reviewed-on: https://chromium-review.googlesource.com/516708Reviewed-by: Ned Nguyen <nednguyen@google.com>
Reviewed-by: rnephew <rnephew@chromium.org>
Commit-Queue: Juan Antonio Navarro Pérez <perezju@chromium.org>
Cr-Commit-Position: refs/heads/master@{#476289}

tools/perf/page_sets/system_health/long_running_stories.py

@@ -92,6 +92,7 @@ class _LongRunningGmailDesktopBase(_LongRunningGmailBase):
         'document.getElementById("loading").style.display === "none"')
 
 
+@decorators.Disabled('android')  # crbug.com/726301
 class LongRunningGmailMobileForegroundStory(_LongRunningGmailMobileBase):
   NAME = 'long_running:tools:gmail-foreground'
 
@@ -101,7 +102,7 @@ class LongRunningGmailDesktopForegroundStory(_LongRunningGmailDesktopBase):
 
 
 @decorators.Disabled('android-webview',  # Weview does not have tabs.
-                     'android')  # crbug.com/657433
+                     'android')  # crbug.com/726301
 class LongRunningGmailMobileBackgroundStory(_LongRunningGmailMobileBase):
   BACKGROUND = True
   NAME = 'long_running:tools:gmail-background'