py3: replace file() with open() in test-win32text.t

This patch also adds b'' prefix to make sure we write bytes on Python 3.

Differential Revision: https://phab.mercurial-scm.org/D2113

tests/test-win32text.t

@@ -5,9 +5,9 b''
   > import sys
   > 
   > for path in sys.argv[1:]:
-  >     data = file(path, 'rb').read()
-  >     data = data.replace('\n', '\r\n')
-  >     file(path, 'wb').write(data)
+  >     data = open(path, 'rb').read()
+  >     data = data.replace(b'\n', b'\r\n')
+  >     open(path, 'wb').write(data)
   > EOF
   $ echo '[hooks]' >> .hg/hgrc
   $ echo 'pretxncommit.crlf = python:hgext.win32text.forbidcrlf' >> .hg/hgrc
@@ -118,7 +118,7 b' and now for something completely differe'
   $ hg rem f
   $ hg ci -m 4
 
-  $ $PYTHON -c 'file("bin", "wb").write("hello\x00\x0D\x0A")'
+  $ $PYTHON -c 'open("bin", "wb").write(b"hello\x00\x0D\x0A")'
   $ hg add bin
   $ hg ci -m 5
   $ hg log -v
@@ -342,7 +342,7 b' and now for something completely differe'
   
   $ rm .hg/hgrc
   $ (echo some; echo text) > f3
-  $ $PYTHON -c 'file("f4.bat", "wb").write("rem empty\x0D\x0A")'
+  $ $PYTHON -c 'open("f4.bat", "wb").write(b"rem empty\x0D\x0A")'
   $ hg add f3 f4.bat
   $ hg ci -m 6
   $ cat bin
@@ -395,7 +395,7 b' Disable warning:'
   $ cat f4.bat
   rem empty\r (esc)
 
-  $ $PYTHON -c 'file("f5.sh", "wb").write("# empty\x0D\x0A")'
+  $ $PYTHON -c 'open("f5.sh", "wb").write(b"# empty\x0D\x0A")'
   $ hg add f5.sh
   $ hg ci -m 7
   $ cat f5.sh