Remove harmony provider and default SecureRandom impl.

These things are effectively unused and there's no point in
carting around all this excess baggage.

This change also removes some other classes that weren't being
used anywhere.

(cherry picked from commit 04270c61ba90e164732a227aaa40065009a21378)

Change-Id: I3813c06c60f09e3db99544bc0a2dcf569ff2f50e
12 files changed