[Merged by Bors] - Fix var collisions in strict eval calls

[jedel1043]

This Pull Request allows collisions of var declarations with already existing lexical bindings if the eval call is strict or occurs within strict code. In short, it allows:

{
  let x;
  {
    eval('"use strict"; var x;');
  }
}

and

"use strict";
{
  let x;
  {
    eval('var x;');
  }
}

This is valid since in strict code all eval calls get their own function environment, making it impossible to declare a new var in the outer function environment. This change also skips poisoning environments on strict code, because eval cannot add new declarations for the current environment in that situation.

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	93,789	93,789	0
Passed	69,176	69,179	+3
Ignored	18,352	18,352	0
Failed	6,261	6,258	-3
Panics	0	0	0
Conformance	73.76%	73.76%	+0.00%

Fixed tests (3):

test/language/eval-code/direct/var-env-lower-lex-strict-source.js [strict mode] (previously Failed)
test/language/eval-code/direct/var-env-lower-lex-strict-source.js (previously Failed)
test/language/eval-code/direct/var-env-lower-lex-strict-caller.js [strict mode] (previously Failed)

[codecov]

Codecov Report

Merging #2382 (a66a08a) into main (8a5f141) will increase coverage by 0.09%.
The diff coverage is 21.21%.

@@            Coverage Diff             @@
##             main    #2382      +/-   ##
==========================================
+ Coverage   39.93%   40.02%   +0.09%     
==========================================
  Files         304      304              
  Lines       23308    23306       -2     
==========================================
+ Hits         9307     9328      +21     
+ Misses      14001    13978      -23     

Impacted Files	Coverage Δ
boa_engine/src/builtins/eval/mod.rs	11.42% <0.00%> (-1.48%)	⬇️
boa_engine/src/context/mod.rs	35.80% <0.00%> (+1.04%)	⬆️
boa_engine/src/syntax/parser/expression/unary.rs	50.94% <33.33%> (-1.89%)	⬇️
boa_engine/src/environments/runtime.rs	28.00% <42.85%> (+3.00%)	⬆️
boa_engine/src/job.rs	60.00% <0.00%> (-6.67%)	⬇️
boa_engine/src/vm/opcode/push/array.rs	76.47% <0.00%> (-3.53%)	⬇️
boa_engine/src/builtins/generator/mod.rs	10.34% <0.00%> (-1.02%)	⬇️
boa_engine/src/builtins/proxy/mod.rs	9.67% <0.00%> (-0.67%)	⬇️
boa_engine/src/builtins/async_generator/mod.rs	6.20% <0.00%> (-0.65%)	⬇️
... and 13 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[Razican]

Thank you!

[jedel1043]

bors r+

[bors]

Pull request successfully merged into main.

Build succeeded:

• Build and Test (macos-latest)
• Build and Test (windows-latest)
• Coverage
• Misc