Add Java 8 style SNI hostname to OpenSSLEngineImpl

[kruton]

The SNIHostName, et al., support was lacking from OpenSSLEngineImpl
causing endpoint protocol identification to fail in Netty tests.

[nmittler]

@kruton can you add a simple test or two for this?

[kruton]

This would be in the integration tests in Android's libcore project.

[kruton]

Here are the two tests I made for this in the libcore integration tests:
https://android-review.googlesource.com/355187
https://android-review.googlesource.com/355188

Adding this actually found a bug in the existing endpointIdentificationAlgorithm tests. Also the added test found the problem you ran into with CertificateException being propagated instead of SSLHandshakeException.

[nmittler]

@kruton you'll want to rebase on the latest master and add any new public getters/setters to the Conscrypt class.

[nmittler]

@kruton also, it would be good to add one or two similar tests to https://github.com/google/conscrypt/blob/master/openjdk/src/test/java/org/conscrypt/OpenSSLEngineImplTest.java

[kruton]

Maybe I can use a pared-down Conscrypt Android build manifest in Travis-CI builds to make sure we don't have a regression until #153 is 100% fixed. That will allow us to run the Android tests until we can separate the tests into its own project.

[nmittler]

Sounds reasonable ... You have something in mind? Want to throw together a PR?

[kruton]

Yes, I will put it together.