Delete @removed-at-birth storage APIs

These APIs never shipped in a final SDK, but were marked @removed
instead of actually removed (to maintain compatibility with DPs).

It's been a while, so just delete them now.
    added ag/1769530 + various other CLs
    removed ag/2118535

A similar cleanup was done in ag/2544851

Bug: 155877914
Test: m
Change-Id: I0ded7c92872c5fbcdad2b96fc30341a1c405152e