test: use consistent block spacing

In preparation for enabling an ESLint rule, use consistent block
spacing. This changes only six files in the code base as block spacing
is consistent throughout the rest of the code base.

Before:  function(c) {data += c;}

After: function(c) { data += c; }

PR-URL: https://github.com/nodejs/node/pull/10377
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Julian Duque <julianduquej@gmail.com>

test/parallel/test-buffer-alloc.js

@@ -988,7 +988,7 @@ assert.throws(() => Buffer.from('', 'buffer'), TypeError);
 {
   let a = [0];
   for (let i = 0; i < 7; ++i) a = a.concat(a);
-  a = a.map((_, i) => {return i;});
+  a = a.map((_, i) => { return i; });
   const b = Buffer.from(a);
   const c = Buffer.from(b);
   assert.strictEqual(b.length, a.length);