test: replace concatenation with template literals

* test/parallel/test-stdout-close-catch.js PR-URL: #14298 Reviewed-By: Rich Trott <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Tobias Nießen <[email protected]> Reviewed-By: Timothy Gu <[email protected]> Reviewed-By: James M Snell <[email protected]>

Author: leizongmin

test/parallel/test-stdout-close-catch.js

@@ -6,9 +6,9 @@ const child_process = require('child_process');
 
 consttestScript=path.join(common.fixturesDir,'catch-stdout-error.js');
 
-constcmd=JSON.stringify(process.execPath)+' '+
-JSON.stringify(testScript)+' | '+
-JSON.stringify(process.execPath)+' '+
+constcmd=`${JSON.stringify(process.execPath)} `+
+`${JSON.stringify(testScript)} | `+
+`${JSON.stringify(process.execPath)} `+
 '-pe "process.stdin.on(\'data\' , () => process.exit(1))"';
 
 constchild=child_process.exec(cmd);