Fix string prototype trim methods

[HalidOdat]

It changes the following:

• Fixed String.prototype.trim()
• Fixed String.prototype.trimStart()
• Fixed String.prototype.trimEnd()
• Add tests

[codecov]

Codecov Report

Merging #583 into master will increase coverage by 0.19%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #583      +/-   ##
==========================================
+ Coverage   70.69%   70.88%   +0.19%     
==========================================
  Files         177      177              
  Lines       11290    11314      +24     
==========================================
+ Hits         7981     8020      +39     
+ Misses       3309     3294      -15     

Impacted Files	Coverage Δ
boa/src/builtins/string/mod.rs	41.85% <100.00%> (+4.74%)	⬆️
boa/src/builtins/string/tests.rs	100.00% <100.00%> (ø)

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[github-actions]

Benchmark for 6e78db9

Click to view benchmark

Test	PR Benchmark	Master Benchmark	%
Arithmetic operations (Execution)	329.6±21.16ns	311.1±17.61ns	+5.95%
Arithmetic operations (Full)	138.8±9.97µs	140.7±9.05µs	-1.35%
Array access (Execution)	12.0±0.94µs	11.7±0.81µs	+2.56%
Array access (Full)	157.1±9.14µs	159.8±13.00µs	-1.69%
Array creation (Execution)	3.2±0.18ms	3.3±0.18ms	-3.03%
Array creation (Full)	3.6±0.23ms	3.5±0.22ms	+2.86%
Array pop (Execution)	1251.9±73.59µs	1265.0±73.56µs	-1.04%
Array pop (Full)	1639.9±118.17µs	1559.9±80.84µs	+5.13%
Boolean Object Access (Execution)	3.6±0.27µs	3.7±0.24µs	-2.70%
Boolean Object Access (Full)	159.8±33.41µs	148.9±13.42µs	+7.32%
Create Realm	134.7±9.36µs	132.0±8.87µs	+2.05%
Dynamic Object Property Access (Execution)	5.5±0.41µs	5.8±0.34µs	-5.17%
Dynamic Object Property Access (Full)	152.9±14.36µs	155.8±13.00µs	-1.86%
Expression (Lexer)	1929.2±103.30ns	2.0±0.16µs	-3.54%
Expression (Parser)	4.7±0.33µs	4.6±0.34µs	+2.17%
Fibonacci (Execution)	848.2±58.19µs	845.4±56.79µs	+0.33%
Fibonacci (Full)	1056.2±96.86µs	1024.8±75.95µs	+3.06%
For loop (Execution)	19.2±1.27µs	19.2±1.40µs	0.00%
For loop (Full)	164.8±21.36µs	161.7±13.97µs	+1.92%
For loop (Lexer)	4.4±0.45µs	4.3±0.27µs	+2.33%
For loop (Parser)	11.7±0.78µs	12.1±0.82µs	-3.31%
Goal Symbols (Parser)	7.3±0.48µs	7.3±0.50µs	0.00%
Hello World (Lexer)	694.8±50.85ns	686.7±41.45ns	+1.18%
Hello World (Parser)	1897.6±139.75ns	1889.7±167.71ns	+0.42%
Long file (Parser)	5.4±0.26ms	5.4±0.27ms	0.00%
Number Object Access (Execution)	2.7±0.20µs	2.8±0.17µs	-3.57%
Number Object Access (Full)	150.2±9.19µs	149.6±11.42µs	+0.40%
Object Creation (Execution)	4.8±0.28µs	4.9±0.31µs	-2.04%
Object Creation (Full)	169.0±13.32µs	169.6±12.74µs	-0.35%
RegExp (Execution)	58.7±3.72µs	58.7±4.54µs	0.00%
RegExp (Full)	209.5±15.00µs	212.2±15.15µs	-1.27%
RegExp Literal (Execution)	62.2±12.21µs	61.3±3.71µs	+1.47%
RegExp Literal (Full)	216.7±16.07µs	217.0±23.24µs	-0.14%
RegExp Literal Creation (Execution)	57.6±3.44µs	59.0±3.84µs	-2.37%
RegExp Literal Creation (Full)	259.6±17.45µs	257.3±19.10µs	+0.89%
Static Object Property Access (Execution)	5.1±0.50µs	4.9±0.32µs	+4.08%
Static Object Property Access (Full)	151.1±14.17µs	150.6±9.57µs	+0.33%
String Object Access (Execution)	6.9±0.66µs	6.9±0.51µs	0.00%
String Object Access (Full)	152.4±9.59µs	155.3±9.95µs	-1.87%
String comparison (Execution)	5.6±0.37µs	5.5±0.42µs	+1.82%
String comparison (Full)	149.2±14.19µs	148.5±9.81µs	+0.47%
String concatenation (Execution)	4.7±0.46µs	4.6±0.35µs	+2.17%
String concatenation (Full)	148.4±8.52µs	148.1±8.18µs	+0.20%
String copy (Execution)	3.6±0.20µs	3.6±0.33µs	0.00%
String copy (Full)	146.3±12.58µs	142.1±8.47µs	+2.96%
Symbols (Execution)	3.1±0.21µs	3.1±0.20µs	0.00%
Symbols (Full)	141.3±9.25µs	139.7±10.58µs	+1.15%