UnitTestNode should subscribe test events on create

Fix no result color displayed on tree node if do not perform expand-collapse-expand actions.

Author: linquize

src/AddIns/Analysis/UnitTesting/Pad/UnitTestNode.cs

@@ -37,6 +37,10 @@ public UnitTestNode(ITest test)
 			if (test == null)
 				throw new ArgumentNullException("test");
 			this.test = test;
+			if (IsVisible) {
+				test.DisplayNameChanged += test_NameChanged;
+				test.ResultChanged += test_ResultChanged;
+			}
 		}
 
 		protected override void OnIsVisibleChanged()