fix(test): Fix test failure on IE11
fix(test): Fix test failure on IE11

One subtlety of the filterDescribe() helper in our tests is that it
does not stop the body of the describe() block from being executed.
It only suppresses the execution of the various "before/after" blocks
and the tests in it().  So the new functional unit tests on factory
functions failed on IE, since the various definitions being eval'd for
the tests were set in the describe() body.  Now they are created in
beforeAll(), which is supressed on non-ES6 platforms.

Change-Id: Ia92c7aa33a89e0217bf9a0394b43753f120ec16d

shaka-project/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player