Revert "Smooth realtime display frame pacing"

This reverts commit a8e9729b3a.

scripts/test_websocket_runtime.mjs

@@ -37,5 +37,5 @@ metrics.addEventListener('message', (event) => {
 await new Promise((resolve) => setTimeout(resolve, 1100));
 sockets.forEach((socket) => socket.close());
 assert.equal(invalidPayload, false, 'metrics must be ordered and contain no large visual payloads');
-assert.ok(count >= 110 && count <= 145, `expected about 120 metrics/s, received ${count}`);
+assert.ok(count >= 50 && count <= 75, `expected about 60 metrics/s, received ${count}`);
 console.log(`runtime websocket test passed (${count} metrics in 1.1 s; max frame age ${maxFrameAgeMs} ms; all three streams opened)`);