The function dumpbvtypes has no use case anymore, so we remove it with
this change.

Change-Id: I1e0323542be2bcc683b75dffde76b222e087c285
Reviewed-on: https://go-review.googlesource.com/66370Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>