Clock, Timer: Drop fallback to Date.now().

[satelllte]

Related issue: #8112

Description

It's probably a time to drop Date.now fallback in Clock & Timer classes, because the support for high resolution timestamp has already been good for years.

Browser: https://developer.mozilla.org/en-US/docs/Web/API/Performance/now
Node: https://nodejs.org/docs/latest-v8.x/api/perf_hooks.html#perf_hooks_performance_now (supported since v8.5.0)

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
685.4 kB (169.7 kB)	685.4 kB (169.7 kB)	-38 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

Filesize dev	Filesize PR	Diff
462 kB (111.4 kB)	462 kB (111.4 kB)	+0 B

[Mugen87]

The newer Timer class in addons/misc/ uses Date.now() as a fallback as well.

three.js/examples/jsm/misc/Timer.js

Line 118 in d7f2d9a

return ( typeof performance === 'undefined' ? Date : performance ).now();

While you are at it, please update this module, too.

In any event, give us some time to think about unexpected side effects with this removal.

[Mugen87]

Let's this a try!