Further reduce LM memory cost

Reduce number of generated synthetic accessors for private var/methods,
put ProviderRequest listener into lazily loaded class, and switch to
ArrayMap instead of WeakHashMap when server-side transport removal is
not a consideration. Also adds support for replacing an old transport
in a single remote call, rather than two remote calls.

Bug: 13463193
Test: none
Change-Id: I09dab317dc82aeda51422af1047274631081c3e1