This test case will turn on the first party isolation and try to open two tabs that the first tab is the opener of the second tab. It will test for different settings and making sure that postMessage cannot go across with the targetOrigin '*' for different FPDs when the pref 'privacy.firstparty.isolate.block_post_message' is enabled. Depends on D8521 Differential Revision: https://phabricator.services.mozilla.com/D8522