rust: update the rust-cpython crate to 0.7.0
This notably brings support for Python 3.10, and includes the panic message
when propagating a Rust panic as a Python exception.
https://github.com/dgrunwald/rust-cpython/blob/master/CHANGELOG.md#070---2021-10-09
Differential Revision: https://phab.mercurial-scm.org/D11630
#require no-pure
A script to generate nasty diff worst-case scenarios:
$ cat > s.py <<EOF
> import random
> for x in range(100000):
> print
> if random.randint(0, 100) >= 50:
> x += 1
> print(hex(x))
> EOF
$ hg init a
$ cd a
Check in a big file:
$ "$PYTHON" ../s.py > a
$ hg ci -qAm0
Modify it:
$ "$PYTHON" ../s.py > a
Time a check-in, should never take more than 10 seconds user time:
$ hg ci --time -m1 --config worker.enabled=no
time: real .* secs .user [0-9][.].* sys .* (re)