Bug 1652086: Make kind_dependencies_tasks a dictionary based on the label; r=Callek

I was looking at py-spy for generating the taskgraph, and found that a bunch
of time was spent in taskgraph.transforms.job.use_fetches[1]. Use a dictionary
there instead saves about 20-30s on my machine.

[1] https://searchfox.org/mozilla-central/rev/622dbd3409610ad3f71b56c9a6a92da905dab0aa/taskcluster/taskgraph/transforms/job/__init__.py#243-247

Differential Revision: https://phabricator.services.mozilla.com/D83166