go/types, types2: remove predecl. test functions from ordinary tests
The type checker implements additional built-in functions (assert
and trace) that are useful for debugging. Only permit them in
manual tests (go test -run Manual), not for other tests where they
are not needed.
Change-Id: Idc7723d9e3f6b2c27769b34743561e9d0339565c
Reviewed-on: https://go-review.googlesource.com/c/go/+/393659
Trust: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Findley <rfindley@google.com>