-Instead of failing at initializing array with negative size.
Introducing PowerMock test for the zero-size array case.
Negative-size case not tested thx to unhelping PowerMock behavior.
Using ConnectionMockTest instead of ConnectionTest; needed by PowerMock.

[FIXED JENKINS-12629] Using jenkins-cli connecting to HTTPS port fails due to hostname mismatch in certificate.

- NoCheckTrustManager needed to implement X509TrustManager not just plain TrustManager