Add class Instruction to simplify ExecutionEngine

[erikzhang]

No description provided.

[erikzhang]

@shargon After you approve this PR, I will create a new PR which uses ReadOnlySpan to optimize byte array replication.

[shargon]

I think that we can initialize RandomAccessStack for start with a optimal capacity and prevent the first redimension of the internal list

[erikzhang]

I think that we can initialize RandomAccessStack for start with a optimal capacity and prevent the first redimension of the internal list

What do you mean?

[erikzhang]

@shargon I reverted the change of upgrading .netstandard to 2.0. If you need to use reflection, you can add it back. Now I will start to work on ReadOnlySpan.

[shargon]

What do you mean?

RandomAccessStack use a list, and list could be initialized with the desired initial capacity.

If we look inside the list we have an array, and is redimensionated according to the length.

By default this array started with 0 length

But we can define a better one, like 32, or just 4, and prevent this first redimension

[erikzhang]

But you don't know how much space will the contract use.

[shargon]

Agree, but at least 4, is the minimum for one item

[erikzhang]

I think there is almost no difference between 0 and 4. The capacity is for large List.

[shargon]

This way is better :)

[shargon]

I think that with your last changes, we don't need reflection :)

[erikzhang]

OK. Then I will merge it first.

[shargon]

I really like the change that this PR gives, good job!