tests/qtest: Enable qtest build on Windows

Now that we have fixed various test case issues as seen when running
on Windows, let's enable the qtest build on Windows.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20221125114100.3184790-4-bmeng.cn@gmail.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/qtest/meson.build

@@ -1,9 +1,3 @@
-# All QTests for now are POSIX-only, but the dependencies are
-# really in libqtest, not in the testcases themselves.
-if not config_host.has_key('CONFIG_POSIX')
-  subdir_done()
-endif
-
 slow_qtests = {
   'ahci-test' : 60,
   'bios-tables-test' : 120,