windows: use umask 022 in debugstate output
debugstate would always report files as mode 666 or 777 on Windows.
umask is not used on Windows, but faking and using a defalt value of 022
matches what the test suite uses on Unix.
basic test for hg debugrebuildstate
$ hg init repo
$ cd repo
$ touch foo bar
$ hg ci -Am 'add foo bar'
adding bar
adding foo
$ touch baz
$ hg add baz
$ hg rm bar
$ hg debugrebuildstate
state dump after
$ hg debugstate --nodates | sort
n 644 -1 bar
n 644 -1 foo
status
$ hg st -A
! bar
? baz
C foo