[autotest] Validate fields of bug template through check_control_files

Add a check in presubmit_hooks to validate bug template defined in test control
files.

BUG=chromium:358493
TEST=pick a control file, add a invalid bug template, try to submit CL:
BUG_TEMPLATE = {'owner': 'invalid_email'}
Confirm repo upload failed with:
autotest_lib.server.cros.dynamic_suite.reporting_utils.InvalidBugTemplateException: Invalid email address: invalid_email.

Change-Id: Ifb643307c7ec6defeba883867a3beee29fd68bf2
Reviewed-on: https://chromium-review.googlesource.com/199297
Reviewed-by: Dan Shi <dshi@chromium.org>
Tested-by: Dan Shi <dshi@chromium.org>
Commit-Queue: Dan Shi <dshi@chromium.org>
3 files changed