feat: implement 0x9F - SWAP16 Opcode

[Eikix]

Kakarot v0 implementation: https://github.com/kkrt-labs/kakarot/blob/main/src/kakarot/instructions/exchange_operations.cairo
Kakarot v0 tests: https://github.com/kkrt-labs/kakarot/blob/44dabfcab05a87f85bcfe0a457809059d11d83fb/tests/src/kakarot/instructions/test_exchange_operations.cairo#L107

EELS Implementation: https://github.com/ethereum/execution-specs/blob/fade6e95726c9c0b47b779fd8873b5737fbea3b3/src/ethereum/paris/vm/instructions/stack.py#L108

Since	Group
Frontier	Exchange Operations

Index 1 is top of the stack. See PUSH.

Stack input

1. a: value to swap.
2. ignored value.
3. ignored value.
4. ignored value.
5. ignored value.
6. ignored value.
7. ignored value.
8. ignored value.
9. ignored value.
10. ignored value.
11. ignored value.
12. ignored value.
13. ignored value.
14. ignored value.
15. ignored value.
16. ignored value.
17. b: value to swap.

Stack output

1. b: swapped value.
2. ignored value.
3. ignored value.
4. ignored value.
5. ignored value.
6. ignored value.
7. ignored value.
8. ignored value.
9. ignored value.
10. ignored value.
11. ignored value.
12. ignored value.
13. ignored value.
14. ignored value.
15. ignored value.
16. ignored value.
17. a: swapped value.

Example

	Input	Output
1	1	2
2	0	0
3	0	0
4	0	0
5	0	0
6	0	0
7	0	0
8	0	0
9	0	0
10	0	0
11	0	0
12	0	0
13	0	0
14	0	0
15	0	0
16	0	0
17	2	1

Reproduce in playground.

Error cases

The state changes done by the current context are reverted in those cases:

• Not enough gas.
• Not enough values on the stack.

[Eikix]

Important update: we are gathering some bugs in the Kakarot v0 codebase, we need to make sure each issue and each PR in Kakarot-ssj is aware of the lists of known bugs. Look at this tracking issue everytime you take an issue and check your issue isn't targeted by a known bug.