Backed out for causing gecko decision bustage

• backout: https://hg.mozilla.org/integration/autoland/rev/268dbf5f503dc24d90e6f1aa1d1849e7f343cafc

• push: https://treeherder.mozilla.org/jobs?repo=autoland&group_state=expanded&selectedTaskRun=R9NXYdptQxux0PFRq3Gl-A.0&revision=b745ade60c2c36554dc36c12c1258f010190b4d8

• failure log: https://treeherder.mozilla.org/logviewer?job_id=364073670&repo=autoland&lineNumber=618

[task 2022-01-13T22:57:09.499Z] Generating tasks for toolchain rustc-dist-toolchain
[task 2022-01-13T22:57:09.501Z] Error loading tasks for kind toolchain:
[task 2022-01-13T22:57:09.501Z] Traceback (most recent call last):
[task 2022-01-13T22:57:09.501Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/generator.py", line 313, in _run
[task 2022-01-13T22:57:09.501Z]     self._write_artifacts,
[task 2022-01-13T22:57:09.501Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/generator.py", line 90, in load_tasks
[task 2022-01-13T22:57:09.502Z]     for task_dict in transforms(trans_config, inputs)
[task 2022-01-13T22:57:09.502Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/generator.py", line 78, in <listcomp>
[task 2022-01-13T22:57:09.502Z]     Task(
[task 2022-01-13T22:57:09.502Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 2093, in check_run_task_caches
[task 2022-01-13T22:57:09.502Z]     for task in tasks:
[task 2022-01-13T22:57:09.502Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 2003, in check_task_dependencies
[task 2022-01-13T22:57:09.503Z]     for task in tasks:
[task 2022-01-13T22:57:09.503Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1989, in check_task_identifiers
[task 2022-01-13T22:57:09.503Z]     for task in tasks:
[task 2022-01-13T22:57:09.503Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1970, in chain_of_trust
[task 2022-01-13T22:57:09.503Z]     for task in tasks:
[task 2022-01-13T22:57:09.504Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1761, in build_task
[task 2022-01-13T22:57:09.504Z]     for task in tasks:
[task 2022-01-13T22:57:09.504Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1752, in try_task_config_routes
[task 2022-01-13T22:57:09.504Z]     for task in tasks:
[task 2022-01-13T22:57:09.504Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1742, in try_task_config_chemspill_prio
[task 2022-01-13T22:57:09.504Z]     for task in tasks:
[task 2022-01-13T22:57:09.504Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1732, in try_task_config_env
[task 2022-01-13T22:57:09.505Z]     for task in tasks:
[task 2022-01-13T22:57:09.505Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1694, in add_index_routes
[task 2022-01-13T22:57:09.506Z]     for task in tasks:
[task 2022-01-13T22:57:09.506Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1489, in validate
[task 2022-01-13T22:57:09.506Z]     for task in tasks:
[task 2022-01-13T22:57:09.507Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1466, in task_name_from_label
[task 2022-01-13T22:57:09.507Z]     for task in tasks:
[task 2022-01-13T22:57:09.507Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1421, in set_defaults
[task 2022-01-13T22:57:09.507Z]     for task in tasks:
[task 2022-01-13T22:57:09.508Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/task.py", line 1400, in set_implementation
[task 2022-01-13T22:57:09.508Z]     for task in tasks:
[task 2022-01-13T22:57:09.508Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/cached_tasks.py", line 63, in cache_task
[task 2022-01-13T22:57:09.508Z]     for task in order_tasks(config, tasks):
[task 2022-01-13T22:57:09.508Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/cached_tasks.py", line 18, in order_tasks
[task 2022-01-13T22:57:09.508Z]     pending = deque(tasks)
[task 2022-01-13T22:57:09.509Z]   File "/builds/worker/checkouts/gecko/taskcluster/gecko_taskgraph/transforms/job/__init__.py", line 300, in use_fetches
[task 2022-01-13T22:57:09.509Z]     kind=config.kind, name=name, fetch=fetch_name
[task 2022-01-13T22:57:09.509Z] Exception: Missing fetch job for toolchain-macosx64-cbindgen: linux64-rust-macos-1.57

https://hg.mozilla.org/mozilla-central/rev/f8ff7bc7bcb6
https://hg.mozilla.org/mozilla-central/rev/5d27484d79a4

Looks like a 1.58.1 is on the way: https://github.com/rust-lang/rust/pull/93071

Probably doesn't affect us but do note: https://blog.rust-lang.org/2022/01/20/cve-2022-21658.html

With one week until 1.59, time to create a "Update builders to rustc 1.59", no?

Filed bug 1783073 instead.