Do not use shell for spawned integration nodes

When using the shell for spawning the master and slave integration
processes the shell becomes the process that is returned by the spawn
command.  This in turn means that the SIGINT that was supposed to be
sent to the master and slave processes got ignored by the shell instead.

Fix by spawning the node process directly instead of through a shell.

test/integration/index.js

@@ -33,7 +33,9 @@ async function exec(...args) {
 
 function spawn(name, cmd, waitFor) {
 	return new Promise((resolve, reject) => {
-		let process = child_process.spawn(cmd, { shell: true });
+		console.log(cmd);
+		let parts = cmd.split(" ");
+		let process = child_process.spawn(parts[0], parts.slice(1));
 		let stdout = new server._LineSplitter((line) => {
 			line = line.toString("utf8");
 			if (line.startsWith(waitFor)) {