harness: remove support for modifying GOMAXPROCS
harness: remove support for modifying GOMAXPROCS

The main purpose of harness is to build higher level test suites in Go
rather than testing the Go code itself so this mechanism for exposing
race conditions isn't very important. Pull it out to simplify things.

If someone wanted to do this w/ harness calling Suite.Run multiple times
would be strait forward.

glevand/coreos--mantle,glevand/coreos--mantle,quantum/coreos-mantle,marineam/mantle,marineam/mantle,dm0-/mantle,dm0-/mantle,quantum/coreos-mantle