lib: move duplicate spliceOne into internal/util

lib/url.js and lib/events.js are using the same spliceOne function.
This change is to move it into the internal/util for avoiding duplicate
code.

PR-URL: nodejs/node#16221
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>

Author: starkwang

lib/internal/util.js

@@ -271,6 +271,13 @@ function join(output, separator) {
   return str;
 }
 
+// About 1.5x faster than the two-arg version of Array#splice().
+function spliceOne(list, index) {
+  for (var i = index, k = i + 1, n = list.length; k < n; i += 1, k += 1)
+    list[i] = list[k];
+  list.pop();
+}
+
 module.exports = {
   assertCrypto,
   cachedResult,
@@ -281,10 +288,11 @@ module.exports = {
   filterDuplicateStrings,
   getConstructorOf,
   isError,
+  join,
   normalizeEncoding,
   objectToString,
   promisify,
-  join,
+  spliceOne,
 
   // Symbol used to customize promisify conversion
   customPromisifyArgs: kCustomPromisifyArgsSymbol,

lib/url.js

@@ -28,6 +28,8 @@ const { hexTable } = require('internal/querystring');
 
 const errors = require('internal/errors');
 
+const { spliceOne } = require('internal/util');
+
 // WHATWG URL implementation provided by internal/url
 const {
   URL,
@@ -950,13 +952,6 @@ Url.prototype.parseHost = function parseHost() {
   if (host) this.hostname = host;
 };
 
-// About 1.5x faster than the two-arg version of Array#splice().
-function spliceOne(list, index) {
-  for (var i = index, k = i + 1, n = list.length; k < n; i += 1, k += 1)
-    list[i] = list[k];
-  list.pop();
-}
-
 // These characters do not need escaping:
 // ! - . _ ~
 // ' ( ) * :