Starting with r41924, run-javascriptcore-tests first runs testapi, and bails out if that fails. However, testapi always fails if time zone is not PST: assertEqualsAsUTF8String(o, "Wed Dec 31 1969 16:00:00 GMT-0800 (PST)");
Created attachment 29307 [details] proposed fix
Committed <http://trac.webkit.org/changeset/42315>.