Cache tags and contexts are no longer always sorted

Cache tags and contexts were always sorted regardless of usage, in order to make debugging and testing more convenient, however this added a performance burden to every HTML request.

In general this will not affect any runtime code at all, however some tests may need to account for differently sorted tags/contexts, in most cases the change will look like the following:

Before:

  $this->assertEquals($expected_top_level_contexts, $element['#cache']['contexts'], 'Expected cache contexts found.');

After:

    $this->assertEqualsCanonicalizing($expected_top_level_contexts, $element['#cache']['contexts'], 'Expected cache contexts found.');