tests: force `seq` to print with '\n' EOL

It looks like consistent EOL is the reason for 0605726179a0, but now on py3,
`print()` uses the platform EOL without regard to binary mode.  The tests mostly
use this to loop over a sequence of number in the shell, but there are a handful
that redirect output to a file.  Specifically, this fixes Windows runs of
`test-bundle2-multiple-changegroups.t`, but there may be other tests this fixes.

Some other `tests/*.py` files also set binary mode on stdout, but they also
write bytes directly to `sys.stdout.buffer`.  I'm not doing that here because
PyCharm flags these write calls for passing bytes instead of str (PyCharm is
likely wrong, but possibly confused because the code falls back to `sys.stdout`
if there is no `.buffer` attribute), and it's annoying.

tests/seq.py

@@ -1,33 +1,31
 #!/usr/bin/env python3
 #
 # 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 os
+import io
 import sys
 
-try:
-    import msvcrt
-
-    msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
-    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
-    msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
-except ImportError:
-    pass
+sys.stdout = io.TextIOWrapper(
+    sys.stdout.buffer,
+    sys.stdout.encoding,
+    sys.stdout.errors,
+    newline="\n",
+)
 
 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 range(start, stop, step):
     print(i)