This exposes the features needed to mimic Chrome's ClientHello, which is useful
in testing. Also use bssl_shim's scopers for SSL objects.

Change-Id: Icb88bb00c0a05c27610134d618f466a24f7f757a
Reviewed-on: https://boringssl-review.googlesource.com/4113
Reviewed-by: Adam Langley <agl@google.com>

Change-Id: I2bf0144aaa8b670ff00b8e8dfe36bd4d237b9a8a
Reviewed-on: https://boringssl-review.googlesource.com/3140
Reviewed-by: Adam Langley <agl@google.com>

Initial fork from f2d678e6e8 (1.0.2 beta).

(This change contains substantial changes from the original and
effectively starts a new history.)