When looking for perfherder data collection duplicates, we currently
keep full job objects references, which are then used in case an error
occurs, to display the job names of the duplicates.
But those job objects are yielded and may be modified by other
transforms, and presently, by the time a duplicate is found, the
corresponding job object has been modified such that it has no 'name'
key anymore, leading to a KeyError exception when trying to display
the duplicate error message.
So instead of keeping the job objects, which can change, and which we
don't have a real use for, just keep the job name.
It is really easy to copy and paste taskgraph or mozharness configs
and cause Perfherder data to be written to the same bucket, resulting
in non-useful metrics collection.
This commit adds a taskgraph transform for the "build" kind that
attempts to look for multiple build jobs writing to the same
Perfherder bucket.
It isn't perfect. But it has already flushed out some jobs writing
to the same bucket and therefore producing bimodal Perfherder data.
MozReview-Commit-ID: COyvXwMiM32
