bench: Merge fast_buffer_creation and buffer_creation

benchmark/buffers/buffer_creation.js

@@ -2,6 +2,7 @@ SlowBuffer = require('buffer').SlowBuffer;
 
 var common = require('../common.js');
 var bench = common.createBenchmark(main, {
+  type: ['fast', 'slow'],
   len: [10, 1024],
   n: [1024]
 });
@@ -9,9 +10,10 @@ var bench = common.createBenchmark(main, {
 function main(conf) {
   var len = +conf.len;
   var n = +conf.n;
+  var clazz = conf.type === 'fast' ? Buffer : SlowBuffer;
   bench.start();
   for (var i = 0; i < n * 1024; i++) {
-    b = new SlowBuffer(len);
+    b = new clazz(len);
   }
   bench.end(n);
 }

benchmark/fast_buffer_creation.js

@@ -1,4 +0,0 @@
-for (var i = 0; i < 1e6; i++) {
-  b = new Buffer(10);
-  b[1] = 2;
-}