qunit: Remove redundant testCount expectation

qunit: Remove redundant testCount expectation

QUnit used to have bad state management (a few years ago) at which point it
became useful to verify the number of assertions in case an asynchronous
failure happened, as it would likely go unnoticed.

* Errors outside testStart/testEnd weren't caught.
  QUnit now monitors window.onerror.

* Assertions could be attributed to the wrong test.
  QUnit no longer does this since the assert object is associated with
  the current test through lexical scope.

* assert.async()/done() replaced global semaphore (QUnit.start).

* A test could forget to be marked as async and make no assertions.
  QUnit now marks a test as failed if it makes  0 assertions.
  QUnit also has built-in async tracking for promises.

If a test is not reaching all assertions for some reason, this
will cause an error of some sort that is tracked. If in some
specific scenario this isn't the case, assert.expect() can still
be called (e.g. when expecting 0 assertions), but it'd be worthwhile
to file an upstream bug report in that case.

Follows-up 7c363752, which removed 'QUnit.config.requireExpects' from
our test configuration.

Follows-up c4c7007de6 and various other commits that already removed
the test counts from a subset tests. This commit removes the remainder.

Change-Id: Ie58396ba9c83d27220508481cb97c0fa74487756