Remove unneded num_bindings in Opcodes and CodeBlock

[HalidOdat]

Since the number of bindings is stored in the compiled envionments and when we create the environment we pass it, there is no need to store the num_bindings for the environments

It changes the following:

• Remove unneeded function_environment_push_location field on CodeBlock
• Remove unneeded num_bindings field on CodeBlock
• Remove unneeded num_bindings operand from PushDeclarativeEnvironment opcode
• Remove unneeded num_bindings operand from PushFunctionEnvironment opcode
• Make ByteCompiler::push_compile_environment() return only the index.
• Remove num_bindings field from environment stack methods that push environments.
• Move CodeBlock flags to bitflags field.

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	93,990	93,990	0
Passed	74,620	74,620	0
Ignored	17,622	17,622	0
Failed	1,748	1,748	0
Panics	0	0	0
Conformance	79.39%	79.39%	0.00%

[codecov]

Codecov Report

Merging #2967 (988d453) into main (15749ed) will decrease coverage by 0.01%.
The diff coverage is 77.85%.

@@            Coverage Diff             @@
##             main    #2967      +/-   ##
==========================================
- Coverage   50.02%   50.01%   -0.01%     
==========================================
  Files         446      446              
  Lines       45896    45906      +10     
==========================================
+ Hits        22959    22961       +2     
- Misses      22937    22945       +8     

Impacted Files	Coverage Δ
boa_cli/src/debug/function.rs	0.00% <0.00%> (ø)
boa_engine/src/vm/flowgraph/mod.rs	0.00% <ø> (ø)
boa_engine/src/vm/opcode/mod.rs	45.45% <ø> (ø)
boa_engine/src/vm/opcode/call/mod.rs	22.89% <50.00%> (ø)
boa_engine/src/vm/code_block.rs	55.07% <54.34%> (-0.65%)	⬇️
boa_engine/src/bytecompiler/class.rs	15.60% <56.25%> (-0.20%)	⬇️
boa_engine/src/bytecompiler/declarations.rs	55.44% <80.00%> (-0.09%)	⬇️
boa_engine/src/builtins/eval/mod.rs	65.65% <100.00%> (-0.35%)	⬇️
boa_engine/src/bytecompiler/env.rs	93.33% <100.00%> (ø)
boa_engine/src/bytecompiler/function.rs	90.76% <100.00%> (-0.14%)	⬇️
... and 12 more

... and 11 files with indirect coverage changes

[raskad]

Looks great.

[nekevss]

I like the changes a lot! I'd second the above review about docs. Other than that, great work! 😄