Exclude test that fails on older Angular versions.

Author: crisbeto

src/lib/select/select.spec.ts

@@ -1406,28 +1406,6 @@ describe('MdSelect', () => {
       });
     }));
 
-    it('should be considered invalid when there are no selected options', () => {
-      testInstance.isRequired = true;
-      fixture.detectChanges();
-
-      expect(testInstance.control.valid).toBe(false, 'Should be invalid when the value is null.');
-
-      trigger.click();
-      fixture.detectChanges();
-
-      let option = overlayContainerElement.querySelector('md-option') as HTMLElement;
-
-      option.click();
-      fixture.detectChanges();
-
-      expect(testInstance.control.valid).toBe(true, 'Should be valid when the array has items.');
-
-      option.click();
-      fixture.detectChanges();
-
-      expect(testInstance.control.valid).toBe(false, 'Should be invalid when the array is empty.');
-    });
-
   });
 });