Use names of accessors instead of their entire spans.

src/compiler/utilities.ts

@@ -387,6 +387,8 @@ namespace ts {
             case SyntaxKind.FunctionDeclaration:
             case SyntaxKind.FunctionExpression:
             case SyntaxKind.MethodDeclaration:
+            case SyntaxKind.GetAccessor:
+            case SyntaxKind.SetAccessor:
             case SyntaxKind.TypeAliasDeclaration:
                 errorNode = (<Declaration>node).name;
                 break;