[9.x] Fix the "Implicit conversion from float to int loses precision" error in Timebox Class

[memu]

The "Implicit conversion from float to int loses precision" error could be triggered since the $remainder variable on the line 27 is not always an integer.

framework/src/Illuminate/Support/Timebox.php

Lines 27 to 31 in c86e883

	$remainder = $microseconds - ((microtime(true) - $start) * 1000000);
	if (! $this->earlyReturn && $remainder > 0) {
	$this->usleep($remainder);
	}