IMAP tests are consistently failing

Since Feb 6th some time before 7am UTC the IMAP server is too slow for the default 5 seconds used by "waitForReadyRead"/QTRY_*/etc. and consequently the tests fail.

Temporarily we will blacklist the relevant testcases to unblock other work in qtbase, and let's figure out what's going on there

EDIT by jimis:

Reproducible by connecting to port 143 of qt-test-server. The "welcome" message of cyrusd takes 10-20s to be sent back. The command to measure that from any affected VM is:

time nc -v 10.212.2.216 143 </dev/null

This was fixed by IT like this:

Actually we have one in MAAS for 10.215. but there is no forwarded to it in our AD DNS servers
I added a forwarder and now resolving 10.215. addresses works.

Now the above netcat commands return successfully immediately from the VM with address 10.215.100.152 and the test passes (it failed on the same VM before the fix).

However things still fail in the CI.
https://coin.ci.qt.io/coin/log/qt/qtbase/0887ae14f1d46c825c944d1f1c8ea1258c26fd5f/LinuxUbuntu_22_04x86_64LinuxUbuntu_22_04x86_64GCCqtci-linux-Ubuntu-22.04-x86_64-51-fd40d3Sccache_TestOnly/4cda2faf09bd6c1996eca0d3bef49843f97f76c2/test_1738865307
https://coin.ci.qt.io/coin/log/qt/qtbase/dbacfb4f258e8cbf9df5014aabae0cba5b1bfcfe/LinuxUbuntu_22_04x86_64LinuxUbuntu_22_04x86_64GCCqtci-linux-Ubuntu-22.04-x86_64-51-fd40d3Sccache_TestOnly/4cda2faf09bd6c1996eca0d3bef49843f97f76c2/test_1738863287

Just tried an Ubuntu 22.04 VM, I can't reproduce the issue.