Shared code among proctor-*.go files has been refactored
into common/common.go. The common package is imported in
each proctor binary and a struct is created to implement
the testRunner interface defined in common.go. This allows
for the proctor binaries to be updated without having to
copy/paste the same code across all files. There are no
usage or functionality changes.
PiperOrigin-RevId: 260967080