Fix delete when the property is not configurable

[tofpie]

This Pull Request fixes an issue with delete when the property to delete is not configurable. In this case, delete should not remove the property from the object, and it should return false.

It changes the following:

• The execution of the delete operator

[codecov]

Codecov Report

Merging #1024 (f0eb2e6) into master (e0a135e) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1024      +/-   ##
==========================================
+ Coverage   60.26%   60.31%   +0.05%     
==========================================
  Files         169      169              
  Lines       11412    11418       +6     
==========================================
+ Hits         6877     6887      +10     
+ Misses       4535     4531       -4     

Impacted Files	Coverage Δ
boa/src/syntax/ast/node/operator/unary_op/mod.rs	69.84% <100.00%> (+1.50%)	⬆️
boa/src/builtins/function/mod.rs	75.72% <0.00%> (ø)
boa/src/environment/global_environment_record.rs	21.05% <0.00%> (ø)
boa/src/environment/object_environment_record.rs	23.72% <0.00%> (ø)
boa/src/environment/lexical_environment.rs	67.61% <0.00%> (+0.31%)	⬆️
boa/src/environment/function_environment_record.rs	34.78% <0.00%> (+0.57%)	⬆️
.../src/environment/declarative_environment_record.rs	41.11% <0.00%> (+0.66%)	⬆️
boa/src/object/internal_methods.rs	62.93% <0.00%> (+2.79%)	⬆️

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[Razican]

Nice conformance improvement!

Test262 conformance changes:

Test result	master count	PR count	difference
Total	78,493	78,493	0
Passed	23,335	23,800	+465
Ignored	15,585	15,585	0
Failed	39,573	39,108	-465
Panics	364	364	0
Conformance	29.73	30.32	+0.59%

[Razican]

Looks good, thanks!