fix data url test

lib/fetch/dataURL.js

@@ -614,30 +614,25 @@ function removeHTTPWhitespace (str, leading = true, trailing = true) {
   return i === 0 && j === str.length ? str : str.substring(i, j)
 }
 
-/**
- * @see https://infra.spec.whatwg.org/#ascii-whitespace
- * @param {number} char
- */
-function isASCIIWhitespace (char) {
-  // "\r\n\t\f "
-  return char === 0x00d || char === 0x00a || char === 0x009 || char === 0x00c || char === 0x020
-}
-
 /**
  * @see https://infra.spec.whatwg.org/#strip-leading-and-trailing-ascii-whitespace
  * @param {string} str
  * @param {boolean} [leading=true]
  * @param {boolean} [trailing=true]
  */
 function removeASCIIWhitespace (str, leading = true, trailing = true) {
-  let i = 0; let j = str.length
+  let lead = 0
+  let trail = str.length - 1
+
   if (leading) {
-    while (j > i && isASCIIWhitespace(str.charCodeAt(i))) --i
+    while (lead < str.length && isHTTPWhiteSpace(str.charCodeAt(lead))) lead++
   }
+
   if (trailing) {
-    while (j > i && isASCIIWhitespace(str.charCodeAt(j - 1))) --j
+    while (trail > 0 && isHTTPWhiteSpace(str.charCodeAt(trail))) trail--
   }
-  return i === 0 && j === str.length ? str : str.substring(i, j)
+
+  return lead === 0 && trail === str.length - 1 ? str : str.slice(lead, trail + 1)
 }
 
 module.exports = {