tests/qtest: libqtest: Correct the timeout unit of blocking receive calls for win32

tests/qtest: libqtest: Correct the timeout unit of blocking receive calls for win32

Some qtest cases don't get response from the QEMU executable under
test in time on Windows. It turns out that the socket receive call
got timeout before it receive the complete response.

The timeout value is supposed to be set to 50 seconds via the
setsockopt() call, but there is a difference among platforms.
The timeout unit of blocking receive calls is measured in
seconds on non-Windows platforms but milliseconds on Windows.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20221028045736.679903-10-bin.meng@windriver.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>