Which makes iterating over map stable which is important for serialization and
and even fixes occasional test failures. We use the same ordering here as
NEO 3.0 uses, but it should also be fine for NEO 2.0 because it has no
defined order.
Fixes#809.
Basically, there are three alternative approaches to fixing it:
* allowing both []byte and string for ByteArrayType value
minimal invasion into existing code, but ugly as hell and will probably
backfire at some point
* storing string values in ByteArrayType
incurs quite a number of type conversions (and associated data copying),
though note that these values are not changed usually, so dynamic
properties of []byte are almost irrelevant here
* storing only []byte values in ByteArrayType
makes it impossible to use them as map keys which can be solved in several
ways:
- via an interface (Marshalable)
which is good, but makes testing and comparing values in general harder,
because of keys mismatch
- using serialized Parameter as a key (in a string)
which will need some additional marshaling/unmarshaling
- converting MapType from map to a slice of key-value pairs
not a bad idea as we don't use this map as a map really, the type
itself is all about input/output for real VM types and this approach is
also a bit closer to JSON representation of the Map
