Fix android.net.SSLTest

The test is failing because of lack of visibility (IllegalAccessError).
Also rename it to match the tested class, migrate to JUnit4, and remove
an old test that is unused (suppressed), relies on third-party servers
and is not a proper unit test (would try to make real network requests).

Test: test now passes
Change-Id: I5032a056df83d4f572d89860b52bd85a1993d9dc