-Changed JToken.Children to return an empty iterator rather than erroring

Src/Newtonsoft.Json.Tests/Linq/JValueTests.cs

@@ -148,11 +148,11 @@ namespace Newtonsoft.Json.Tests.Linq
     }
 
     [Test]
-    [ExpectedException(typeof(InvalidOperationException), ExpectedMessage = "Cannot access child value on Newtonsoft.Json.Linq.JValue.")]
     public void Children()
     {
       JValue v = new JValue(true);
       var c = v.Children();
+      Assert.AreEqual(JEnumerable<JToken>.Empty, c);
     }
 
     [Test]

Src/Newtonsoft.Json/Linq/JToken.cs

@@ -265,7 +265,7 @@ namespace Newtonsoft.Json.Linq
     /// <returns>An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> containing the child tokens of this <see cref="JToken"/>, in document order.</returns>
     public virtual JEnumerable<JToken> Children()
     {
-      throw new InvalidOperationException("Cannot access child value on {0}.".FormatWith(CultureInfo.InvariantCulture, GetType()));
+      return JEnumerable<JToken>.Empty;
     }
 
     /// <summary>