[11.x] Add withoutHeader() test method (#52309)

* Add withoutHeader test method

* Update docblock comment

src/Illuminate/Foundation/Testing/Concerns/MakesHttpRequests.php

@@ -90,6 +90,19 @@ public function withHeader(string $name, string $value)
         return $this;
     }
 
+    /**
+     * Remove a header from the request.
+     *
+     * @param  string  $name
+     * @return $this
+     */
+    public function withoutHeader(string $name)
+    {
+        unset($this->defaultHeaders[$name]);
+
+        return $this;
+    }
+
     /**
      * Add an authorization token for the request.
      *
@@ -121,9 +134,7 @@ public function withBasicAuth(string $username, string $password)
      */
     public function withoutToken()
     {
-        unset($this->defaultHeaders['Authorization']);
-
-        return $this;
+        return $this->withoutHeader('Authorization');
     }
 
     /**