Improve bytecompiler bytecode generation.

[HalidOdat]

This PR adds the Operand enum (which represents an instruction operand), and makes ByteCompiler::emit take an array of Operands instead of u32 which allows to emit varying length operands more easily.

[codecov]

Codecov Report

Merging #3188 (15e5dc4) into main (5f70585) will decrease coverage by 0.02%.
Report is 5 commits behind head on main.
The diff coverage is 39.86%.

❗ Current head 15e5dc4 differs from pull request most recent head 8bcb4f8. Consider uploading reports for the commit 8bcb4f8 to get more accurate results

@@            Coverage Diff             @@
##             main    #3188      +/-   ##
==========================================
- Coverage   50.40%   50.38%   -0.02%     
==========================================
  Files         436      436              
  Lines       42375    42432      +57     
==========================================
+ Hits        21358    21381      +23     
- Misses      21017    21051      +34     

Files Changed	Coverage Δ
boa_engine/src/bytecompiler/module.rs	0.00% <0.00%> (ø)
boa_engine/src/module/source.rs	0.00% <0.00%> (ø)
boa_engine/src/vm/opcode/mod.rs	69.23% <ø> (ø)
boa_engine/src/bytecompiler/class.rs	15.15% <5.35%> (-0.42%)	⬇️
boa_engine/src/bytecompiler/declarations.rs	51.28% <10.52%> (-0.36%)	⬇️
...rc/bytecompiler/declaration/declaration_pattern.rs	34.33% <11.11%> (-0.85%)	⬇️
boa_engine/src/bytecompiler/expression/binary.rs	74.62% <28.57%> (ø)
boa_engine/src/bytecompiler/expression/update.rs	55.44% <41.17%> (+1.23%)	⬆️
boa_engine/src/bytecompiler/expression/assign.rs	38.25% <41.66%> (+0.25%)	⬆️
boa_engine/src/bytecompiler/utils.rs	78.57% <50.00%> (+1.82%)	⬆️
... and 5 more

[raskad]

I like the refactor, but there seems to be a bug somewhere since -1,820 tests are failing

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	95,282	95,282	0
Passed	75,036	75,036	0
Ignored	19,220	19,220	0
Failed	1,026	1,026	0
Panics	0	0	0
Conformance	78.75%	78.75%	0.00%

[jedel1043]

Nice refactor!