run-tests: introduce a `HGTEST_REAL_HG` variable for test
It turns out that currently, `hg` and `which hg` can point to different things
because `hg` is an alias… This is annoying because script and pieces of test
are unknowingly using the wrong `hg`.
We will fix it in another changeset. However some test actually need to use a
real `hg` binary and not some `chg` or `rhg` equivalent. So we introduce a new
variable with the right value and we put it to us in the appropriate location.
Differential Revision: https://phab.mercurial-scm.org/D11049
https://bz.mercurial-scm.org/619
$ hg init
$ echo a > a
$ hg ci -Ama
adding a
$ echo b > b
$ hg branch b
marked working directory as branch b
(branches are permanent and global, did you want a bookmark?)
$ hg ci -Amb
adding b
$ hg co -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
Fast-forward:
$ hg merge b
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -Ammerge
Bogus fast-forward should fail:
$ hg merge b
abort: merging with a working directory ancestor has no effect
[255]
Even with strange revset (issue4465)
$ hg merge ::.
abort: merging with a working directory ancestor has no effect
[255]