Deprecate many of the accidentally-published APIs in dalvik.system.

Deprecate many of the accidentally-published APIs in dalvik.system.

See bug 2021674 for discussion. I searched Google Code Search to
sample which of these APIs are being used. None of these APIs
were used by applications, so I'm quite confident that removing
them will not break applications or upset developers.

These APIs were neither formerly documented, nor intended for use
by application developers. I am deprecating them now to discourage
their use going forward. We should remove them in a future release.