dijit test pages should include dijit.dijit or other appropriate roll-up

[alex]

As per an email conversation with Adam, we need to ensure that the Dijit test pages require the dijit.dijit package so that they perform acceptably when viewed from a build.

If another roll-up is needed to handle other common sets of sub-tasks, we should build them and include them in test pages under cover of this bug.

[bill]

Be careful, this might make the CSS race condition problem worse and end up with more tabs/accordions that draw incorrectly.

[peller]

if there's any risk whatsoever, we shouldn't do this for rc.

[alex]

how would this carry risk? I'm deeply confused by this.

[peller]

(In [13735]) Add 'dijit.dijit' to load layer for all tests and improve performance. Fixes #6281