tests: Windows compatibility fixes
- printenv.py, md5sum.py, simplemerge, test-archive, test-merge1,
test-merge-symlinks: set standard streams to binary mode
- test-encode: replace "gunzip" by "gzip -d"
- test-hup: requires fifo
% fail
failed to contact inotify server: No such file or directory
deactivating inotify
abort: could not start server: File exists
% inserve
% status
? hg.pid