Create AbortSignal earlier in new Request()

This regressed in 987c3fd.

Fixes whatwg#1249.

Author: annevk

fetch.bs

@@ -6880,6 +6880,9 @@ constructor steps are:
 
  <li><p>Set <a>this</a>'s <a for=Request>request</a> to <var>request</var>.
 
+ <li><p>Set <a>this</a>'s <a for=Request>signal</a> to a <a for=/>new</a> {{AbortSignal}} object
+ with <a>this</a>'s <a>relevant Realm</a>.
+
  <li><p>If <var>signal</var> is not null, then make <a>this</a>'s <a for=Request>signal</a>
  <a for=AbortSignal>follow</a> <var>signal</var>.
 
@@ -6987,9 +6990,6 @@ constructor steps are:
 
  <li><p>Set <a>this</a>'s <a for=Request>request</a>'s <a for=request>body</a> to
  <var>finalBody</var>.
-
- <li><p>Set <a>this</a>'s <a for=Request>signal</a> to a <a for=/>new</a> {{AbortSignal}} object
- with <a>this</a>'s <a>relevant Realm</a>.
 </ol>
 
 <p>The <dfn attribute for=Request><code>method</code></dfn> getter steps are to return <a>this</a>'s
@@ -7893,6 +7893,7 @@ Lachlan Hunt,
 Larry Masinter,
 Liam Brummitt,
 Louis Ryan,
+Luca Casonato,
 Lucas Gonze,
 Łukasz Anforowicz,
 呂康豪 (Kang-Hao Lu),