tests: handle string escaping/encoding on Python 3
This code was failing on Python 3 for a few reasons:
1) sys.argv is str and str doesn't have a .decode()
2) the "string_escape" encoding was renamed to "unicode_escape"
It is wonky casting to bytes to str to bytes. But this is test
code, so meh. I don't believe we exercise any code paths in these
tests where the arguments aren't ascii.
Differential Revision: https://phab.mercurial-scm.org/D5667
$ hg init repo
$ cd repo
$ touch foo
$ hg ci -Am 'add foo'
adding foo
$ hg up -C null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
this should be stored as a delta against rev 0
$ echo foo bar baz > foo
$ hg ci -Am 'add foo again'
adding foo
created new head
$ hg debugindex foo
rev linkrev nodeid p1 p2
0 0 b80de5d13875 000000000000 000000000000
1 1 0376abec49b8 000000000000 000000000000
$ cd ..