Two bots failed on `gclient runhooks`, closing the tree.

https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/ios-simulator/33601
 - r562312
 - r562313

https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Deterministic%20Linux/13923
 - r562309:562313

Both failed with an exception
Traceback (most recent call last):
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/gclient.py", line 2947, in <module>
    sys.exit(main(sys.argv[1:]))
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/gclient.py", line 2933, in main
    return dispatcher.execute(OptionParser(), argv)
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/subcommand.py", line 252, in execute
    return command(parser, args[1:])
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/gclient.py", line 2671, in CMDrunhooks
    return client.RunOnDeps('runhooks', args)
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/gclient.py", line 1588, in RunOnDeps
    self.RunHooksRecursively(self._options, pm)
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/gclient.py", line 1041, in RunHooksRecursively
    hook.run(self.root.root_dir)
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/gclient.py", line 226, in run
    cmd, cwd=cwd, always=self._verbose)
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/gclient_utils.py", line 314, in CheckCallAndFilterAndHeader
    return CheckCallAndFilter(args, **kwargs)
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/gclient_utils.py", line 525, in CheckCallAndFilter
    **kwargs)
  File "/b/swarming/w/ir/kitchen-checkout/depot_tools/subprocess2.py", line 246, in __init__
    super(Popen, self).__init__(args, **kwargs)
  File "/b/swarming/w/ir/cipd_bin_packages/lib/python2.7/subprocess.py", line 390, in __init__
    errread, errwrite)
  File "/b/swarming/w/ir/cipd_bin_packages/lib/python2.7/subprocess.py", line 1024, in _execute_child
    child_exception = pickle.loads(data)
  File "/b/swarming/w/ir/cipd_bin_packages/lib/python2.7/pickle.py", line 1388, in loads
    return Unpickler(file).load()
  File "/b/swarming/w/ir/cipd_bin_packages/lib/python2.7/pickle.py", line 864, in load
    dispatch[key](self)
  File "/b/swarming/w/ir/cipd_bin_packages/lib/python2.7/pickle.py", line 977, in load_string
    self.append(rep.decode("string-escape"))
LookupError: unknown encoding: string-escape
step returned non-zero exit code: 1

Seems kinda related to Issue 843728 - I left a comment there.

Reopened tree. ios-simulator was green on the next run -> https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/ios-simulator/33602