Better error messaging for perf tryjobs on windows XP.

tools/telemetry/telemetry/core/backends/remote/trybot_browser_finder.py

Index: tools/telemetry/telemetry/core/backends/remote/trybot_browser_finder.py
diff --git a/tools/telemetry/telemetry/core/backends/remote/trybot_browser_finder.py b/tools/telemetry/telemetry/core/backends/remote/trybot_browser_finder.py
index 62b80a35a272108dc3377037f58ac0da0b821897..e593ec8862f85df94692ee400fa5a6967f4d8d34 100644
--- a/tools/telemetry/telemetry/core/backends/remote/trybot_browser_finder.py
+++ b/tools/telemetry/telemetry/core/backends/remote/trybot_browser_finder.py
@@ -234,6 +234,9 @@ def _GetTrybotList():
   builders = json.loads(f.read()).get('builders', {}).keys()
   builders = ['trybot-%s' % b.replace('_perf_bisect', '').replace('_', '-')
               for b in builders if not b.endswith('_perf_bisect_builder')]
+  # Perf try jobs do not work on Windows XP
+  if 'trybot-win-xp' in builders:
+    builders.remove('trybot-win-xp')
   return builders