internal/buildgo: make basepin disks in all zones
internal/buildgo: make basepin disks in all zones

Follow-up to CL 210237.

Updates golang/go#35987

Change-Id: Ib00873123926863ba3d419fb5863adf7aaf4a41e
Reviewed-on: https://go-review.googlesource.com/c/build/+/210498
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Alexander Rakoczy <60c6d277a8bd81de7fdde19201bf9c58a3df08f4@golang.org>

golang/build,golang/build,golang/build,golang/build