map_union_sum: Velox does not accept boolean type while Presto does

[peterenescu]

Bug description

Aggregate function map_union_sum does not accept type boolean and may cause fuzzer failures; however, Presto does accept BOOLEAN as a key type:

> select map_union_sum(x) from (select map(array[true, false], cast(array[1.1,2] as array<real>) ) x union all select map(array[true, false], cast(array[10,20] as array<real>)))
_col0
{
  "false": 22,
  "true": 11.1
}

System information

Unexpected key type BOOLEAN, Source: RUNTIME, ErrorCode: UNREACHABLE_CODE

Relevant logs

[peterenescu]

https://github.com/facebookincubator/velox/commit/9442cef2cf20ea0a657ce7a63ac2c92e9959ed95