exp/types: avoid init race in check_test.go.
There was an init race between
check_test.go:init
universe.go:def
use of Universe
and
universe.go:init
creation of Universe
The order in which init funcs are executed in a package is unspecified.
The test is not currently broken in the golang.org environment
because the go tool compiles the test with non-test sources before test sources,
but other environments may, say, sort the source files before compiling,
and thus trigger this race, causing a nil pointer panic.
R=gri
CC=golang-dev
https://golang.org/cl/
6827076