Keep the composed ini when a forked worker ends

Forked workers inherited the shutdown function deleting the composed ini,
so the first one to end deleted it while PHP processes spawned later in the
run still read their configuration from it through PHPRC.

Amp-Thread-ID: https://ampcode.com/threads/T-01a17e3b-9bb8-77b1-a5c1-722d8ade601b

Author: ondrejmirtes

src/Process/Restart/RestartManager.php

@@ -369,7 +369,14 @@ private static function cleanUpComposedIni(): void
 		// descendants must not delete the file their siblings are still reading
 		putenv(self::TEMPORARY_INI_ENV_VARIABLE);
 
-		register_shutdown_function(static function () use ($temporaryIni): void {
+		// pcntl_fork()ed workers inherit this shutdown function; the first one
+		// to end would delete the ini while the rest of the run still reads it
+		$ownerPid = getmypid();
+		register_shutdown_function(static function () use ($temporaryIni, $ownerPid): void {
+			if (getmypid() !== $ownerPid) {
+				return;
+			}
+
 			@unlink($temporaryIni);
 		});