test-logtoprocess: don't run on Windows

Several bits of output were missing[1], unless the DETACHED_PROCESS flag is
_not_ passed to subprocess.Popen().  The problem with that is it briefly opens
and closes several cmd.exe windows on screen.  Foozy also mentioned some other
issues in that thread.

With this, the last of the long standing Windows failures fixed, the test suite
now runs cleanly (536 ran, 67 skipped) on Windows 7 x64, with python 2.7.13. \o/

[1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-April/096987.html

tests/test-logtoprocess.t

@@ -1,73 +1,75 b''
+#require no-windows
+
 ATTENTION: logtoprocess runs commands asynchronously. Be sure to append "| cat"
 to hg commands, to wait for the output, if you want to test its output.
 Otherwise the test will be flaky.
 
 Test if logtoprocess correctly captures command-related log calls.
 
   $ hg init
   $ cat > $TESTTMP/foocommand.py << EOF
   > from mercurial import registrar
   > from time import sleep
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > @command('foo', [])
   > def foo(ui, repo):
   >     ui.log('foo', 'a message: %(bar)s\n', bar='spam')
   > EOF
   $ cp $HGRCPATH $HGRCPATH.bak
   $ cat >> $HGRCPATH << EOF
   > [extensions]
   > logtoprocess=
   > foocommand=$TESTTMP/foocommand.py
   > [logtoprocess]
   > command=echo 'logtoprocess command output:';
   >     echo "\$EVENT";
   >     echo "\$MSG1";
   >     echo "\$MSG2"
   > commandfinish=echo 'logtoprocess commandfinish output:';
   >     echo "\$EVENT";
   >     echo "\$MSG1";
   >     echo "\$MSG2";
   >     echo "\$MSG3"
   > foo=echo 'logtoprocess foo output:';
   >     echo "\$EVENT";
   >     echo "\$MSG1";
   >     echo "\$OPT_BAR"
   > EOF
 
 Running a command triggers both a ui.log('command') and a
 ui.log('commandfinish') call. The foo command also uses ui.log.
 
 Use sort to avoid ordering issues between the various processes we spawn:
   $ hg foo | cat | sort
   
   
   
   0
   a message: spam
   command
   commandfinish
   foo
   foo
   foo
   foo
   foo exited 0 after * seconds (glob)
   logtoprocess command output:
   logtoprocess commandfinish output:
   logtoprocess foo output:
   spam
 
 Confirm that logging blocked time catches stdio properly:
   $ cp $HGRCPATH.bak $HGRCPATH
   $ cat >> $HGRCPATH << EOF
   > [extensions]
   > logtoprocess=
   > pager=
   > [logtoprocess]
   > uiblocked=echo "\$EVENT stdio \$OPT_STDIO_BLOCKED ms command \$OPT_COMMAND_DURATION ms"
   > [ui]
   > logblockedtimes=True
   > EOF
 
   $ hg log | cat
   uiblocked stdio [0-9]+.[0-9]* ms command [0-9]+.[0-9]* ms (re)