Also trigger analyze exclusion for python files in testing/buildbot.

This is a followup to r514556 per comments in https://chromium-review.googlesource.com/c/chromium/tools/build/+/758799/.

Bug: 
Change-Id: If42ea0e4bd43f10a5a44f7ce16dd4c721c9f3603
Reviewed-on: https://chromium-review.googlesource.com/761976
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515481}

testing/buildbot/trybot_analyze_config.json

@@ -23,6 +23,7 @@
       "infra/scripts/.*",
       "DEPS",
       "testing/buildbot/.*json",
+      "testing/buildbot/.*pyl",
       "testing/scripts/.*",
       "testing/test_env.py",
       "third_party/android_platform/development/scripts/.*",