Update TestTest.php

I'm glad to see I wasn't the only person that had misspelled 'Annotation'.

Author: rquadling

tests/Util/TestTest.php

@@ -821,7 +821,7 @@ public function testGetLinesToBeCoveredSkipsNonExistentMethods()
         );
     }
 
-    public function testTwoCoversDefaultClassAnnoationsAreNotAllowed()
+    public function testTwoCoversDefaultClassAnnotationsAreNotAllowed()
     {
         $this->expectException(CodeCoverageException::class);