QTcpSocket::bind: fix issue found by BLACKLIST

The comment in QNativeSocketEnginePrivate::fetchConnectionParameters()
talked about IPv6 v4-mapped addresses. However, toIPv4Address also
converts the unspecified address (::), which resulted in QAbstractSocket
saying that it had bound to QHostAddress::Any instead of
QHostAddress::AnyV6

Change-Id: I572733186b73423b89e5fffd15f138579c5c0c50
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

src/network/socket/qnativesocketengine_win.cpp

@@ -588,7 +588,8 @@ bool QNativeSocketEnginePrivate::fetchConnectionParameters()
     // local address of the socket which bound on both IPv4 and IPv6 interfaces.
     // This address does not match to any special address and should not be used
     // to send the data. So, replace it with QHostAddress::Any.
-    if (socketProtocol == QAbstractSocket::IPv6Protocol) {
+    const uchar ipv6MappedNet[] = {0,0,0,0, 0,0,0,0, 0,0,0xff,0xff, 0,0,0,0};
+    if (localAddress.isInSubnet(QHostAddress(ipv6MappedNet), 128 - 32)) {
         bool ok = false;
         const quint32 localIPv4 = localAddress.toIPv4Address(&ok);
         if (ok && localIPv4 == INADDR_ANY) {

tests/auto/network/socket/qtcpsocket/BLACKLIST

@@ -1,10 +1,3 @@
-[bind]
-windows-10 msvc-2015
-windows-7sp1
-[bind:[::]]
-windows
-[bind:[::]:randomport]
-windows
 [timeoutConnect:ip]
 windows
 # QTBUG-66247

tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp

@@ -585,7 +585,7 @@ void tst_QTcpSocket::bind()
 
     if (successExpected) {
         bool randomPort = port == -1;
-        int attemptsLeft = 5;     // only used with randomPort
+        int attemptsLeft = 5;     // only used with randomPort or Windows
         do {
             if (randomPort) {
                 // try to get a random port number