CRITICAL: createFile from createVirtualTypeScriptEnvironment does not create a file detectable by it's own updateFile

Page URL: https://github.com/microsoft/TypeScript-Website/blob/v2/packages/typescript-vfs/src/index.ts#L72

Issue: When calling updateFile on a newly created file, an error is thrown, stating Error: Did not find a source file for X. I believe the internal fs mapping does not get updated with the newly created files.

Here's an example:

    import {
        createDefaultMapFromCDN,
        createSystem,
        createVirtualTypeScriptEnvironment
    } from '@typescript/vfs';
    import ts from 'typescript';

    const compilerOpts = {
        target: ts.ScriptTarget.ES2021,
        module: ts.ScriptTarget.ES2020,
        lib: ['es2021', 'es2020', 'dom', 'webworker'],
        esModuleInterop: true
    };

    const fsMap = await createDefaultMapFromCDN(
        compilerOpts,
        ts.version,
        false,
        ts
    );
    const ENTRY_POINT = 'index.ts';
    fsMap.set(ENTRY_POINT, 'Hello World');

    const system = createSystem(fsMap);
    const env = createVirtualTypeScriptEnvironment(
        system,
        [ENTRY_POINT],
        ts,
        compilerOpts
    );

    env.createFile('test.js', 'test')
    env.updateFile('test.js', 'hello world') // throws error

Start at packages/typescript-vfs/src/index.ts around line 72 and reproduce the example using createVirtualTypeScriptEnvironment, createFile, and updateFile. Trace why the newly created test.js is not found, then verify that updating it no longer throws the reported source-file error.