fix(ngSwitch): use the correct transclusion scope

If an ngSwitchWhen or ngSwitchDefault directive is on an element that also
contains a transclusion directive (such as ngRepeat) the new scope should
be the one provided by the bound transclusion function.

Previously we were incorrectly creating a simple child of the main ngSwitch
scope.

Closes #8235
you mean because the test will fail if the behaviour changes? But that's good, otherwise we might not have a clear understanding that behaviour has changed, and the behaviour should always be what we expect it to be.