Rewrote fileToUint8Array function to be also NodeJS/Deno compatible.

[mbuella]

Motivation for the change, related issues

Performing multipart upload and posting of data currently works on the web (client) side. Doing it on PHP WASM instance running on NodeJS or other server runtimes (except Deno) causes this issue due to FileReader not supported on the runtime:

ReferenceError: FileReader is not defined
    at file:///c/Users/alonbuella/Documents/projects/php-wasm-vercel/node_modules/@php-wasm/universal/index.js:1717:15
    at new Promise (<anonymous>)
    at fileToUint8Array (file:///c/Users/alonbuella/Documents/projects/php-wasm-vercel/node_modules/@php-wasm/universal/index.js:1716:10)
    at encodeAsMultipart (file:///c/Users/alonbuella/Documents/projects/php-wasm-vercel/node_modules/@php-wasm/universal/index.js:1702:38)
    at PHPRequestHandler.ce (file:///c/Users/alonbuella/Documents/projects/php-wasm-vercel/node_modules/@php-wasm/universal/index.js:2070:48)
    at PHPRequestHandler.le (file:///c/Users/alonbuella/Documents/projects/php-wasm-vercel/node_modules/@php-wasm/universal/index.js:2056:33)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Implementation details

This PR introduces an alternative to using FileReader in order to determine the Uint8Array value for a File instance. This is creating a new instance of Uint8Array from the file's buffer instead.

File's arrayBuffer instance method and Uint8Array class are both supported on NodeJS and Deno, and as well as on most recent browsers.

Testing Instructions (or ideally a Blueprint)

• Tested locally via npm run test
• CI

[adamziel]

Really good spot and a great fix, thank you! My only ask would be to add either a test or an inline comment to inform the next person to avoid using the FileReader class and why.

[mbuella]

@adamziel thanks for your nice feedback! I have added an inline comment to the updated code to explain why we must avoid using FileReader.

[adamziel]

Thank you @mbuella! The failing test is just a flaky test. Let's merge!