The point of this code is to print a warning about repeated go test
invocations rebuilding the same packages over and over.
The new cache will eliminate this failure mode and with it
the need for the warning and this field.
Change-Id: Ied79b3ca67d51a61f44629de6ae4974e6c8dd5a9
Reviewed-on: https://go-review.googlesource.com/56282 Reviewed-by: David Crawshaw <crawshaw@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>