[release-branch.go1.3] go.tools/present: allow intentionally empty parameters

««« CL 105070043 / 1e6e75afb0cd
go.tools/present: allow intentionally empty parameters

Fixes golang/go#7613.

LGTM=r
R=adg, r
CC=golang-codereviews
https://golang.org/cl/105070043

»»»

LGTM=dsymonds
R=dsymonds
CC=golang-codereviews
https://golang.org/cl/148300043
3 files changed