Strip ?search query off module names

[TomasHubelbauer]

This patch allows relative files in the module import syntax (import something from './mod';) to include a search query part and still resolve to the correct file on disk, as if they relative path was not a part but a URL. Full ESM import URL support is discussed in #41730 and full-support would be ideal! This patch implements only a mid-step towards the full solution, in the form of a special-case for those module names which contain the search query. I use this syntax, but it is otherwise extremely niche, in fact, it is possible no one but me would benefit from this. Still, I figured since I've already written the code, I might as well offer it for upstreaming. The scenario this patch enables that didn't work before is this:

import something from './mod?argument';

The imported module case use the search query value through import.meta.url. This works both in Node and browser runtimes.

• There is an associated issue in the Backlog milestone (required): I'm here to collect feedback, so no ticket in the backlog, but Add (relative) URL imports for modules #41730 is the most relevant ticket for this patch
• Code is up-to-date with the master branch
• You've successfully run gulp runtests locally (npm test is the same thing, right?)
• There are new or updated unit tests validating the change: not yet, I'd like some help with identifying where to add those

Thanks for your feedback.

[typescript-bot]

This PR doesn't have any linked issues. Please open an issue that references this PR. From there we can discuss and prioritise.

[TomasHubelbauer]

I've developed a VS Code extension that serves as a work-around for the lack of this feature in TS:
https://github.com/TomasHubelbauer/vscode-esm-url