[3.0] fix inconsistency in ABI generated for map

[linh2931]

Change Description

Resolve #34.

Please see #34 for detailed problem description and solution discussion.

Previously, map ABI was a pair of key and value. If a pair's component types were the same as a map, depending on the order of map and pair definition, different ABIs for pair were generated.

For example, before the fix, pair_int32_int64 were different depending on my_map was defined before or after my_pair:

std::map<int32_t, int64_t> my_map; 
std::pair<int32_t, int64_t> my_pair;

generates

        {
            "name": "pair_int32_int64",
            "base": "",
            "fields": [
                {
                    "name": "key",
                    "type": "int32"
                },
                {
                    "name": "value",
                    "type": "int64"
                }
            ]
        },
...
        [
                {
                    "name": "my_map",
                    "type": "pair_int32_int64[]"
                },
                {
                    "name": "my_pair",
                    "type": "pair_int32_int64"
                }
        ]

std::pair<int32_t, int64_t> my_pair;
std::map<int32_t, int64_t> my_map;

generates

        {
            "name": "pair_int32_int64",
            "base": "",
            "fields": [
                {
                    "name": "first",
                    "type": "int32"
                },
                {
                    "name": "first",
                    "type": "int64"
                }
            ]
        },
...
       [
                {
                    "name": "my_pair",
                    "type": "pair_int32_int64"
                },
                {
                    "name": "my_map",
                    "type": "pair_int32_int64[]"
                }
       ]

After the fix, both produce the same ABI for pair_int32_int64

    {
         "name": "pair_int32_int64",
         "base": "",
         "fields": [
             {
                 "name": "first",
                 "type": "int32"
             },
             {
                 "name": "second",
                 "type": "int64"
             }
         ]
     },
...
     [
           {
                 "name": "my_map",
                  "type": "pair_int32_int64[]"
           },
           {
                 "name": "my_pair",
                 "type": "pair_int32_int64"
           }
    ]

In addition, Reference Contracts https://github.com/AntelopeIO/reference-contracts were tested against the new CDT and CDT 3.0.0, ABIs generated by both CDTs were the same.

API Changes

• API Changes

Documentation Additions

• Documentation Additions