[build.webkit.org] Use workerEnvironment instead of slaveEnvironment for new Buildbot. New buildbot doesn't support slave terminology and slaveEnvironment should be replaced with workerEnvironment.
<rdar://problem/71118024>
Created attachment 413457 [details] Patch
Committed r269536: <https://trac.webkit.org/changeset/269536> All reviewed patches have been landed. Closing bug and clearing flags on attachment 413457 [details].