Specification compliant ToString (to_string)

[HalidOdat]

This PR makes ToString (to_string) spec compliant.

What was wrong with the previous implementation?

The previous implementation used to ToString trait which was automatically implemented for Display, the problem is that we use different logic for displaying and converting to String type, for example, converting a string value to a String type with displays to_string is "some string value" (don't get the quotes, because the is a bug #373) but with the spec compliant function it's some string value without the quotes.
Additionally the spec compliant version should call to_primitive on objects and if it was to throw an exception it would have to propagate it.

This PR should unblock #373 .

Changes:

• Moved Value display logic to builtins/value/display.rs
• Added to_string to interpreter
• Change most use of displays to_string => interpreters to_string

[github-actions]

Benchmark for 4b86b35

Click to view benchmark

Test	PR Benchmark	Master Benchmark	%
Create Realm	448.1±33.79µs	445.9±34.56µs	100%
Expression (Lexer)	2.2±0.15µs	2.2±0.15µs	100%
Expression (Parser)	5.1±0.37µs	5.0±0.39µs	102%
Fibonacci (Execution)	2.8±0.18ms	2.9±0.18ms	98%
For loop (Execution)	463.9±29.04µs	483.3±42.29µs	96%
For loop (Lexer)	5.6±0.37µs	5.8±0.47µs	96%
For loop (Parser)	14.8±1.31µs	13.8±0.72µs	107%
Hello World (Lexer)	1082.6±99.57ns	1069.4±86.52ns	101%
Hello World (Parser)	2.4±0.18µs	2.4±0.20µs	99%
Symbols (Execution)	474.7±35.97µs	472.1±26.63µs	101%
	undefined	undefined	100%

[Razican]

Looks very good, I added some comments in places I thought we could improve readability, mostly :)

[github-actions]

Benchmark for 8be4ad9

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Test	PR Benchmark	Master Benchmark	%
Create Realm	385.8±22.33µs	394.5±24.61µs	98%
Expression (Lexer)	1874.8±124.62ns	1855.3±101.68ns	101%
Expression (Parser)	4.6±0.29µs	4.8±0.25µs	97%
Fibonacci (Execution)	2.6±0.12ms	2.6±0.13ms	100%
For loop (Execution)	417.5±29.20µs	453.0±22.94µs	90.99999999999999%
For loop (Lexer)	4.9±0.37µs	5.1±0.35µs	96%
For loop (Parser)	12.6±0.74µs	12.5±0.98µs	100%
Hello World (Lexer)	896.5±57.41ns	900.0±61.90ns	100%
Hello World (Parser)	2.1±0.11µs	2.1±0.14µs	101%
Symbols (Execution)	426.3±27.67µs	434.0±33.07µs	98%
	undefined	undefined	100%

[codecov]

Codecov Report

Merging #425 into master will decrease coverage by 0.08%.
The diff coverage is 56.76%.

@@            Coverage Diff             @@
##           master     #425      +/-   ##
==========================================
- Coverage   66.72%   66.64%   -0.09%     
==========================================
  Files         123      124       +1     
  Lines        8809     8852      +43     
==========================================
+ Hits         5878     5899      +21     
- Misses       2931     2953      +22     

Impacted Files	Coverage Δ
boa/src/builtins/object/mod.rs	27.16% <0.00%> (ø)
boa/src/builtins/value/conversions.rs	44.59% <ø> (-1.46%)	⬇️
boa/src/builtins/value/mod.rs	58.60% <ø> (-2.22%)	⬇️
boa/src/exec/expression/mod.rs	71.42% <0.00%> (ø)
boa/src/builtins/console/mod.rs	27.31% <9.09%> (-3.68%)	⬇️
boa/src/builtins/string/mod.rs	36.90% <36.11%> (+0.14%)	⬆️
boa/src/builtins/bigint/mod.rs	52.63% <50.00%> (-1.92%)	⬇️
boa/src/builtins/number/mod.rs	71.35% <57.89%> (-1.23%)	⬇️
boa/src/exec/mod.rs	54.51% <70.58%> (+1.20%)	⬆️
boa/src/builtins/array/mod.rs	80.94% <75.00%> (+0.35%)	⬆️
... and 7 more

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[github-actions]

Benchmark for f92de8e

Click to view benchmark

Test	PR Benchmark	Master Benchmark	%
Create Realm	469.6±17.02µs	459.1±13.94µs	102%
Expression (Lexer)	2.2±0.04µs	2.2±0.03µs	101%
Expression (Parser)	5.3±0.21µs	5.4±0.22µs	99%
Fibonacci (Execution)	2.8±0.06ms	2.8±0.05ms	100%
For loop (Execution)	480.6±11.75µs	470.4±7.70µs	102%
For loop (Lexer)	5.7±0.16µs	5.8±0.12µs	99%
For loop (Parser)	14.3±0.47µs	14.5±1.16µs	99%
Hello World (Lexer)	1038.0±20.58ns	1048.7±19.74ns	99%
Hello World (Parser)	2.4±0.06µs	2.4±0.23µs	99%
Symbols (Execution)	487.4±5.82µs	483.9±10.21µs	101%
	undefined	undefined	100%

[Razican]

This is good to go! :)