child_process: refactor normalizeSpawnArguments()

Code is not in hot path. Refactor ternary to be more readable if/else
block that mirrors analogous code elsewhere in the function. Change
string concatenation to template literal.

PR-URL: #14149
Reviewed-By: Vse Mozhet Byt <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Michaël Zasso <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Refael Ackermann <[email protected]>

Author: Trott

lib/child_process.js

@@ -442,9 +442,11 @@ function normalizeSpawnArguments(file, args, options) {
     const command = [file].concat(args).join(' ');
 
     if (process.platform === 'win32') {
-      file = typeof options.shell === 'string' ? options.shell :
-              process.env.comspec || 'cmd.exe';
-      args = ['/d', '/s', '/c', '"' + command + '"'];
+      if (typeof options.shell === 'string')
+        file = options.shell;
+      else
+        file = process.env.comspec || 'cmd.exe';
+      args = ['/d', '/s', '/c', `"${command}"`];
       options.windowsVerbatimArguments = true;
     } else {
       if (typeof options.shell === 'string')