Fix "gulp benchmark" for Windows
Fix "gulp benchmark" for Windows

I'm presuming this task worked fine on Linux, but I use a Windows 10 laptop, and since Windows doesn't open extensionless files to check their shebang, this task failed.

Node.js on the other hand ignore's JavaScript files with a shebang, so this simple fix should make it work on all platforms now.

Mingun/pegjs,pegjs/pegjs,Mingun/pegjs,pegjs/pegjs