Add Forge Now: Use different views for each tab
This is more manageable than handling it manually with URL fragments (which repeatedly breaks when adding new tabs).
This is just like !762 (closed), except there is no redirect from the old URLs (not needed, as this feature was not deployed yet)
Test Plan
This includes an ugly workaround in a test, because makes the tests run into an existing bug. !764 (closed) will fix that bug
Migrated from D7439 (view on Phabricator)