Fix some realmless ArrayBuffer creation

Test: web-platform-tests/wpt#46104.

Fixes #1675.

Author: bakkot

fetch.bs

@@ -7139,8 +7139,9 @@ steps:
     <p>Run <var>action</var>.
 
     <p>Whenever one or more bytes are available and <var>stream</var> is not
-    <a for=ReadableStream>errored</a>, <a for=ReadableStream>enqueue</a> a {{Uint8Array}} wrapping
-    an {{ArrayBuffer}} containing the available bytes into <var>stream</var>.
+    <a for=ReadableStream>errored</a>, <a for=ReadableStream>enqueue</a> the result of
+    [=ArrayBufferView/create|creating=] a {{Uint8Array}} from the available bytes into
+    <var>stream</var>.
 
     <p>When running <var>action</var> is done, <a for=ReadableStream>close</a> <var>stream</var>.
   </ol>
@@ -7274,8 +7275,8 @@ algorithm, given an object that includes {{Body}} <var>object</var> and an algor
 <div algorithm>
 <p>The <dfn method for=Body><code>arrayBuffer()</code></dfn> method steps are to return the result
 of running <a for=Body>consume body</a> with <a>this</a> and the following step given a
-<a for=/>byte sequence</a> <var>bytes</var>: return a new {{ArrayBuffer}} whose contents are
-<var>bytes</var>.
+<a for=/>byte sequence</a> <var>bytes</var>: return the result of [=ArrayBuffer/creating=] an
+{{ArrayBuffer}} from <var>bytes</var> in <a>this</a>'s <a>relevant realm</a>.
 
 <p class="note">The above method can reject with a {{RangeError}}.
 </div>
@@ -7291,7 +7292,7 @@ and whose {{Blob/type}} attribute is the result of <a for=Body>get the MIME type
 
 <div algorithm>
 <p>The <dfn method for=Body><code>formData()</code></dfn> method steps are to return the result of
-running <a for=Body>consume body</a> with <a>this</a> and the following step given a
+running <a for=Body>consume body</a> with <a>this</a> and the following steps given a
 <a for=/>byte sequence</a> <var>bytes</var>:
 
 <ol>