test-electron: don't show window when running without --debug

test/electron/index.js

@@ -24,6 +24,7 @@ app.on('ready', () => {
 	const win = new BrowserWindow({
 		height: 600,
 		width: 800,
+		show: false,
 		webPreferences: {
 			backgroundThrottling: false,
 			webSecurity: false
@@ -31,8 +32,8 @@ app.on('ready', () => {
 	});
 
 	win.webContents.on('did-finish-load', () => {
-		win.show();
 		if (debug) {
+			win.show();
 			win.webContents.openDevTools('right');
 		}
 		win.webContents.send('run', { grep, run });