when deserialize for Map, value is re-serialized

[cloud8little]

Describe the bug
when deserialize the type Map, value is re-serialized.

neo/src/neo/SmartContract/JsonSerializer.cs

Lines 45 to 56 in 5e96011

	case Map map:
	{
	var ret = new JObject();
	foreach (var entry in map)
	{
	if (!(entry.Key is ByteString)) throw new FormatException();
	var key = entry.Key.GetString();
	var value = Serialize(entry.Value);
	ret[key] = value;

when serialize the type Map, keep the original key and value.

neo/src/neo/SmartContract/JsonSerializer.cs

Lines 106 to 115 in 5e96011

	case Map map:
	writer.WriteStartObject();
	stack.Push(JsonTokenType.EndObject);
	foreach (var pair in map.Reverse())
	{
	if (!(pair.Key is ByteString)) throw new FormatException();
	stack.Push(pair.Value);
	stack.Push(pair.Key);
	stack.Push(JsonTokenType.PropertyName);
	}

To Reproduce
Steps to reproduce the behavior:

1. deploy the following contract.

        public static object testdeserialize(string a )
        {
            Map<string, string> some = new Map<string, string>();
            some[a] = "testbool";
            string sea = Json.Serialize(some);
            return Json.Deserialize(sea);
        }

2. invoke method.

Expected behavior
Serialize and deserialize should be consistent.

Screenshots

Platform:

• OS:Windows 10 x64

[erikzhang]

L54 is in Serialize() not Deserialize().

[erikzhang]

The issue is in L155.