This reverts commit 6da88ec19eea2780c030dc95fcc55d059fed69e5.
Removing existing handlers turns out to be load-bearing for Jasmine's
parallel mode. ParallelWorker (in the jasmine package) installs a pair
of handlers before booting core so that it can catch late async errors
that happen after one spec file has finished executing and before the
next starts. If those aren't uninstalled, errors that get routed through
jasmine-core's normal error handling mechanism will also be reported
via ParallelWorker's handlers. It might be possible for ParallelWorker
to uninstall and install its handlers at the right time, but it's
likely that there would be gaps in between when core uninstalls its
handlers and when ParallelWorker installs. And in any case, the
old behavior of GlobalErrors was a perfect match for what ParallelWorker
needs, so let's keep it.
88289f592e