tests/seq.py

tests: restore 'python' and '$TESTDIR/' for dummyssh invocation

This is a backout of 46727fea7a00, and a partial backout of c3ecbf694904.

Windows won't execute 'dummyssh' directly, presumably because CreateProcess()
doesn't know how to execute a bash script:

   $ hg clone -e "dummyssh" ssh://user@dummy/cloned sshclone
   remote: 'dummyssh' is not recognized as an internal or external command,
   remote: operable program or batch file.
   abort: no suitable response from remote hg!
   [255]

With the restoration of python as the executable, $TESTDIR needs to be restored
for these invocations, because python won't search $PATH for 'dummyssh':

   $ hg clone -e "python dummyssh" ssh://user@dummy/cloned sshclone
   remote: python: can't open file 'dummyssh': [Errno 2] No such file or directory
   abort: no suitable response from remote hg!
   [255]

#!/usr/bin/env python
#
# A portable replacement for 'seq'
#
# Usage:
#   seq STOP              [1, STOP] stepping by 1
#   seq START STOP        [START, STOP] stepping by 1
#   seq START STEP STOP   [START, STOP] stepping by STEP

import sys

start = 1
if len(sys.argv) > 2:
    start = int(sys.argv[1])

step = 1
if len(sys.argv) > 3:
    step = int(sys.argv[2])

stop = int(sys.argv[-1]) + 1

for i in xrange(start, stop, step):
    print i