LP#1268619 disable shared workers pending browser issues

LP#1268619 disable shared workers pending browser issues

There appears to be a bug in Chromium where loading the same page
multiple times (without a refresh or cache clear) causes the
SharedWorker to fail to instantiate on every other page load.
Further research pending.  Disabling SharedWorker's entirely for
now.

Note, to replicate, load a page using shared workers, focus the
browser address bar, hit Enter to load the page again.  The shared
worker will fail to load on every other page load, though it will
appear to the SharedWorker caller (opensrf.js) that the port is open.

Signed-off-by: Bill Erickson <berick@esilibrary.com>