cmd/bench: add flag overrides for all environment variables

This change adds a flag for the experiment and baseline GOROOTs, as well
as a flag for the branch. This both adds documentation as to where
cmd/bench gets these values from, and allows users running this command
manually to override them without modifying their environment.

Change-Id: Iba9e3bc70687989fe6fc40e3a810b21aa5091dfe
Reviewed-by: Michael Pratt <>
Trust: Michael Knyszek <>
Run-TryBot: Michael Knyszek <>
TryBot-Result: Gopher Robot <>
1 file changed