perf!: avoid extra copies of immediate args

[Oppen]

The Instruction structure no longer keeps a copy of whatever value follows the tentative instruction. If it's an immediate, other fields are enough to deduce that. If the argument is missing, memory access will make that evident.
There's no need for that copy.

Because a public field of a public structure is gone, it's a breaking change.

Checklist

• Linked to Github Issue
• Unit tests added
• Integration tests added.
• This change requires new documentation.
  • Documentation has been added/updated.
  • CHANGELOG has been updated.

[codecov]

Codecov Report

Merging #942 (242ba16) into main (21b6427) will increase coverage by 0.01%.
The diff coverage is 97.41%.

❗ Current head 242ba16 differs from pull request most recent head 2413d53. Consider uploading reports for the commit 2413d53 to get more accurate results

@@            Coverage Diff             @@
##             main     #942      +/-   ##
==========================================
+ Coverage   98.14%   98.15%   +0.01%     
==========================================
  Files          85       85              
  Lines       34576    34536      -40     
==========================================
- Hits        33934    33899      -35     
+ Misses        642      637       -5     

Impacted Files	Coverage Δ
src/vm/context/run_context.rs	99.71% <ø> (-0.01%)	⬇️
src/vm/vm_core.rs	97.87% <90.90%> (+0.01%)	⬆️
src/types/instruction.rs	95.91% <95.83%> (ø)
src/utils.rs	99.44% <100.00%> (+<0.01%)	⬆️
src/vm/decoding/decoder.rs	100.00% <100.00%> (+0.41%)	⬆️
src/vm/runners/cairo_runner.rs	98.13% <100.00%> (+0.02%)	⬆️
src/vm/trace/mod.rs	97.10% <100.00%> (+2.29%)	⬆️

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[github-actions]

Benchmark Results for unmodified programs 🚀

Command	Mean [s]	Min [s]	Max [s]	Relative
base blake2s_integration_benchmark	21.983 ± 0.168	21.759	22.363	1.06 ± 0.01
head blake2s_integration_benchmark	20.690 ± 0.194	20.378	21.016	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base compare_arrays_200000	6.750 ± 0.130	6.593	7.020	1.09 ± 0.02
head compare_arrays_200000	6.186 ± 0.071	6.057	6.309	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base dict_integration_benchmark	4.205 ± 0.054	4.116	4.262	1.08 ± 0.02
head dict_integration_benchmark	3.901 ± 0.051	3.838	3.999	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base factorial_multirun	7.286 ± 0.077	7.170	7.393	1.10 ± 0.02
head factorial_multirun	6.624 ± 0.064	6.542	6.768	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base fibonacci_1000_multirun	6.369 ± 0.145	6.237	6.768	1.10 ± 0.03
head fibonacci_1000_multirun	5.794 ± 0.047	5.704	5.860	1.00

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
base field_arithmetic_get_square_benchmark	248.4 ± 5.1	242.4	258.0	1.05 ± 0.03
head field_arithmetic_get_square_benchmark	237.1 ± 4.7	229.2	244.4	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base integration_builtins	20.624 ± 0.250	20.259	20.965	1.07 ± 0.02
head integration_builtins	19.329 ± 0.277	19.009	19.831	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base keccak_integration_benchmark	22.518 ± 0.409	22.179	23.454	1.07 ± 0.02
head keccak_integration_benchmark	21.140 ± 0.250	20.880	21.693	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base linear_search	6.740 ± 0.073	6.673	6.915	1.08 ± 0.02
head linear_search	6.252 ± 0.060	6.165	6.359	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base math_cmp_and_pow_integration_benchmark	4.459 ± 0.048	4.383	4.562	1.08 ± 0.02
head math_cmp_and_pow_integration_benchmark	4.141 ± 0.038	4.050	4.193	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base math_integration_benchmark	4.209 ± 0.048	4.145	4.328	1.08 ± 0.01
head math_integration_benchmark	3.909 ± 0.021	3.872	3.938	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base memory_integration_benchmark	3.790 ± 0.050	3.703	3.868	1.10 ± 0.02
head memory_integration_benchmark	3.449 ± 0.034	3.392	3.484	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base operations_with_data_structures_benchmarks	4.092 ± 0.034	4.042	4.148	1.07 ± 0.01
head operations_with_data_structures_benchmarks	3.819 ± 0.032	3.766	3.870	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base pedersen	1.312 ± 0.012	1.295	1.328	1.03 ± 0.02
head pedersen	1.267 ± 0.018	1.247	1.297	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base poseidon_integration_benchmark	2.164 ± 0.022	2.136	2.201	1.04 ± 0.02
head poseidon_integration_benchmark	2.085 ± 0.036	2.026	2.165	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base secp_integration_benchmark	5.073 ± 0.032	5.034	5.144	1.04 ± 0.01
head secp_integration_benchmark	4.862 ± 0.053	4.772	4.953	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base set_integration_benchmark	2.855 ± 0.028	2.806	2.895	1.03 ± 0.02
head set_integration_benchmark	2.759 ± 0.031	2.720	2.799	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
base uint256_integration_benchmark	12.731 ± 0.182	12.503	13.014	1.06 ± 0.02
head uint256_integration_benchmark	11.969 ± 0.222	11.735	12.413	1.00

[fmoletta]

LGTM!

[pefontana]

nice one!