CSHARP-2305: Support strings as value for $numberInt.

Author: rstam

src/MongoDB.Bson/IO/JsonReader.cs

@@ -1559,6 +1559,10 @@ private BsonValue ParseNumberIntExtendedJson()
             {
                 value = valueToken.Int32Value;
             }
+            else if (valueToken.Type == JsonTokenType.String)
+            {
+                value = JsonConvert.ToInt32(valueToken.StringValue);
+            }
             else
             {
                 var message = string.Format("JSON reader expected an integer but found '{0}'.", valueToken.Lexeme);

tests/MongoDB.Bson.Tests/IO/JsonReaderTests.cs

@@ -529,6 +529,9 @@ public void TestInt32()
         [InlineData("{ $numberInt : 1 }", 1)]
         [InlineData("{ $numberInt : -2147483648 }", -2147483648)]
         [InlineData("{ $numberInt : 2147483647 }", 2147483647)]
+        [InlineData("{ $numberInt : \"1\" }", 1)]
+        [InlineData("{ $numberInt : \"-2147483648\" }", -2147483648)]
+        [InlineData("{ $numberInt : \"2147483647\" }", 2147483647)]
         public void TestInt32ExtendedJson(string json, int expectedResult)
         {
             using (var reader = new JsonReader(json))