libbinder: static assert wire protocol sizes

These can change until the RPC protocol is frozen (this may be in a
later or earlier release), but in the spirit of keeping the tree in as
close of a release state as possible, adding these asserts here now.

Bug: 182938972
Test: build (build time static asserts)
Change-Id: I682a75fb20a1249c4da4a8b6957ae6448b934f9f