MEMCPY.json in Tests/ is not a valid JSON

[fyrchik]

It has // comments which are not permitted by JSON specification.
https://github.com/neo-project/neo-vm/blob/master/tests/neo-vm.Tests/Tests/OpCodes/Splice/MEMCPY.json

[ixje]

Perhaps this is a good moment to revive #94 and agree on a standard to enforce for NEO3? We can use a json schema + validator to make sure all json files pass.

Other items I'd like to include:

• not all tests have a name field (e.g. TRHOW, ABORT,ASSERT, PUSHM1_to_PUSH16, PUSHINT8_to_PUSHINT256.json)
• hex strings are sometimes prefixed with 0x and sometimes not. Let's just fix them in some format (either with or without)
• Restrict elements in the list under the script key to be either an instruction name or a hex string. Not "PUSH0*1048576" like CAT.json has.