Remove failing test.

Helper::domId() was removed, remove the test case.

tests/TestCase/View/HelperTest.php

@@ -778,16 +778,6 @@ class HelperTest extends TestCase {
 	}
 
 /**
- * testDomId method
- *
- * @return void
- */
-	public function testDomId() {
-		$result = $this->Helper->domId('Foo.bar');
-		$this->assertEquals('FooBar', $result);
-	}
-
-/**
  * testMultiDimensionalField method
  *
  * @return void