Expose SSLContext.SSL as an alias for SSLContext.TLS

SSL was removed with SSLv3 however a lot of callers use
SSL instead of Default leading to breakage.

Test: libcore/run-libcore-tests
libcore/luni/src/test/java/libcore/javax/net/ssl/*
Bug:32584776
Bug:30977793

Change-Id: I7ce48488a28e2c62bb0c2a76261a11fbd5bb9da7