check-code: allow importing Python 3 modules Now that we no longer support Python 2, we should be able to import and use the Python 3 only modules in our code. So remove a lint banning this. Differential Revision: https://phab.mercurial-scm.org/D12284

tests: move Python 3.5 check higher in file Per code review comment on the changeset that introduced the Python 3.5+ checks. Differential Revision: https://phab.mercurial-scm.org/D12259

py2: drop some more from __future__ statements These are no longer needed after dropping support for Python 2. Differential Revision: https://phab.mercurial-scm.org/D12258

tests: delete some no-py3 blocks And drop some nearby avoidable py3 checks in close proximity while we are here. Differential Revision: https://phab.mercurial-scm.org/D12257

tests: remove __future__ import from test-debugcommands.t This one is slightly more involved since it affects test output. Differential Revision: https://phab.mercurial-scm.org/D12256

tests: remove from __future__ from inline Python in tests This is no longer required since we require Python 3 and the linter no longer requires these statements. Differential Revision: https://phab.mercurial-scm.org/D12255

py2: remove simple from __future__ statements These were needed for Python 2 support. Now that our linter no longer mandates these, we can start deleting them. Differential Revision: https://phab.mercurial-scm.org/D12254

tests: remove output conditionalized on no-py3 I simply did a search for `^.* \(no-py3 !\)\n` and removed all matched lines. There are still some references to no-py3. But these were the simpler ones to match against. Differential Revision: https://phab.mercurial-scm.org/D12253