gotest: avoid conflicts with the name of the tested package
gotest: avoid conflicts with the name of the tested package

Uses a generic solution of renaming the tested package, instead of
using cryptic names for all other imports, variables and methods
in the generated _testmain.go file.

Fixes issue 2346.

R=golang-dev, r, adg
CC=golang-dev, rsc
http://codereview.appspot.com/5254061

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

dsriram/golang,pombredanne/go-deleteme,tv42/old-go,dsriram/golang,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,apparentlymart/golang,apparentlymart/golang,tv42/old-go,pombredanne/go-deleteme,dsriram/golang,gnanderson/go,tv42/old-go,dsriram/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,apparentlymart/golang,apparentlymart/golang,gnanderson/go,gnanderson/go,pombredanne/go-deleteme,gnanderson/go,pombredanne/go-deleteme,tv42/old-go,apparentlymart/golang,gnanderson/go,gnanderson/go,dsriram/golang,apparentlymart/golang,gnanderson/go,tv42/old-go,apparentlymart/golang,dsriram/golang,dsriram/golang