feat: add subarray prototype method in fixed-endian-factory

[DhruvArvindSingh]

Added necessary changes in test ,benchmark and README.md files

Fixes : #3157

This PR adds 'subarray' prototype method in array/fixed-endian-factory.

Updated files(array/fixed-endian-factory):

• README.md
• main.js

Added files(array/fixed-endian-factory):

• benchmark.subarray.length.js
• benchmark.subarray.js
• test.subarray.js

Read, understood, and

• Read, understood, and followed the contributing guidelines.

---

@stdlib-js/reviewers

[DhruvArvindSingh]

Kindly review this PR @kgryte

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
array/fixed-endian-factory	$\color{red}1266/1521$ $\color{green}+83.23\%$	$\color{red}175/189$ $\color{green}+92.59\%$	$\color{red}24/34$ $\color{green}+70.59\%$	$\color{red}1266/1521$ $\color{green}+83.23\%$

The above coverage report was generated for the changes in this PR.

[Vinit-Pandit]

Suggested change

	setReadOnly( TypedArray.prototype, 'subarray', function subarray( begin, end) {
	setReadOnly( TypedArray.prototype, 'subarray', function subarray( begin, end ) {