[netty#5874] [netty#5971] Ensure SniHandlerTest.testServerNameParsing…

… not fails with SslProvider.JDK

Motivation:

The SniHandlerTest.testServerNameParsing did fail when SslProvider.JDK was used as it the JDK SSLEngineImpl does not send an alert.

Modifications:

Ensure tests pass with JDK and OPENSSL ssl implementations.

Result:

SniHandlerTest will run with all SslProvider and not fail when SslProvider.JDK is used.