tests: fix http-bad-server expected errors for python 3.10 (issue6643) The format of the error message changed with this version of Python. This also removes obsolete Python 3 checks.

status: let `--no-copies` override `ui.statuscopies`

run-tests: display the time it took to install Mercurial It will help make people aware of this critical step and to assess the time it takes in various options (like a CI run for example).

run-tests: deal with distutil deprecation PEP 632 recommend the use of `packaging.version` to replace the deprecated `distutil.version`. So lets do it.

fsmonitor: migrate Python ABCs from collections to collections.abc The Collections Abstract Base Classes in the collections module are deprecated since Python 3.3 in favor of collections.abc, and removed in Python 3.10.

templates: add filter to reverse list The filter supports only lists because for lists, it’s straightforward to implement. Reversing text doesn’t seem very useful and is hard to implement. Reversing the bytes would break multi-bytes encodings. Reversing the code points would break characters consisting of multiple code points. Reversing graphemes is non-trivial without using a library not included in the standard library.

requires: re-use vfs.tryread for simplicity Avoids calling `set` twice or having to re-raise an exception and implements the routine with a single return expression.