packagestest.Modules is now available pre-go1.11 but doesn't add
itself to packagestest.All.
strings.ReplaceAll is not available in pre-go1.11
Change-Id: Ia8bf0e82bb853c6f29d31ca5c54651097342b19c
Reviewed-on: https://go-review.googlesource.com/c/143419
Reviewed-by: Ian Cottrell <iancottrell@google.com>
Alan Donovan