Fix attributes on properties of functions and constructors

[tofpie]

This Pull Request fixes the attributes on properties length and name of functions and constructors. These properties should be configurable (see spec for length and spec for name).

It changes the following:

• Default attributes of name and length for functions and constructors
• Add name property to built-ins functions

[codecov]

Codecov Report

Merging #1023 (cb54e4d) into master (57d5679) will increase coverage by 0.02%.
The diff coverage is 90.00%.

@@            Coverage Diff             @@
##           master    #1023      +/-   ##
==========================================
+ Coverage   60.23%   60.26%   +0.02%     
==========================================
  Files         169      169              
  Lines       11408    11412       +4     
==========================================
+ Hits         6872     6877       +5     
+ Misses       4536     4535       -1     

Impacted Files	Coverage Δ
boa/src/object/mod.rs	51.51% <66.66%> (+0.27%)	⬆️
boa/src/builtins/function/mod.rs	75.72% <100.00%> (+0.98%)	⬆️

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[Razican]

This looks great! Thanks!

Test262 conformance changes:

Test result	master count	PR count	difference
Total	78,493	78,493	0
Passed	22,657	23,335	+678
Ignored	15,585	15,585	0
Failed	40,251	39,573	-678
Panics	364	364	0
Conformance	28.86	29.73	+0.86%