all: delete obsolete/unsupported packages

Per discussion in proposal #25503, delete a number of packages which
were at best unmaintained and at worst completely broken. We don't think
anyone is using these.

IF THIS CHANGE BREAKS YOU:
Please file a bug on the main Go issue tracker and we'll try to work
something out. Go 1.11 will definitely cause problems for any users of
these packages without some work.

Change-Id: I19365e87d84c9a295bf6cf705a001992839a7dc7
Reviewed-on: https://go-review.googlesource.com/121017
Run-TryBot: Heschi Kreinick <heschi@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>