lint: Put opening brace on same line as function

Normally I would let `eslint --fix` do this for me, but there's a bug
that causes:

    const x = function ()
    {
      // ...
    };

to become:

    const x = ()
    => {
      // ...
    };

which ESLint thinks is a syntax error. (It probably is; I don't know
enough about the automatic semicolon insertion rules to be confident.)

tests/frontend/helper.js

@@ -16,8 +16,7 @@ var helper = {};
     });
   }
 
-  helper.randomString = function randomString(len)
-  {
+  helper.randomString = function randomString(len) {
     var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
     var randomstring = '';
     for (var i = 0; i < len; i++)