run-tests: rely on an actual executable in PATH instead of alias for `hg`
The alias approach is poorly inherited by other process that the test might
spawn.
To solve this we use the same approach as for `python`/`python3` we write an
executable file explicitly. Doing this fixes `which hg` invocation that now
returns the same location as `hg`.
Using chg server side has some minor effect on some stdout/stderr ordering when
using `chg` as the server too.
Differential Revision: https://phab.mercurial-scm.org/D11053
$ hg init r1
$ cd r1
$ hg ci --config ui.allowemptycommit=true -m c0
$ hg ci --config ui.allowemptycommit=true -m c1
$ hg ci --config ui.allowemptycommit=true -m c2
$ hg co -q 0
$ hg ci --config ui.allowemptycommit=true -m c3
created new head
$ hg co -q 3
$ hg merge --quiet
$ hg ci --config ui.allowemptycommit=true -m c4
$ hg log -G -T'{desc}'
@ c4
|\
| o c3
| |
o | c2
| |
o | c1
|/
o c0
>>> from mercurial import hg
>>> from mercurial import ui as uimod
>>> repo = hg.repository(uimod.ui())
>>> for anc in repo.changelog.ancestors([4], inclusive=True):
... print(anc)
4
3
2
1
0