Restores the ability of H2 in default configuration to use ssl
connections out-of-the-box.

The security property jdk.tls.legacyAlgorithms exists in newer Java
versions and its default value effectively prevents anonymous TLS
from being used. The modification is only attempted when
h2.enableAnonymousTLS is true and makes SSL server socket behaviour
during handshake more similar to that of older JREs.

Note that the setting affects all SSL server sockets on the same JVM.