[Fetch] Body consume function should not set bodyUsed flag.

LayoutTests/http/tests/fetch/script-tests/response.js

Index: LayoutTests/http/tests/fetch/script-tests/response.js
diff --git a/LayoutTests/http/tests/fetch/script-tests/response.js b/LayoutTests/http/tests/fetch/script-tests/response.js
index 4fb92e8ec156af137b104f5fa6300decd9bafe02..b3fc72ef8f75f7960a894cb64fa57cbd5a80decb 100644
--- a/LayoutTests/http/tests/fetch/script-tests/response.js
+++ b/LayoutTests/http/tests/fetch/script-tests/response.js
@@ -493,4 +493,19 @@ promise_test(function(t) {
         });
   }, 'Extract a MIME type (3)');
 
+promise_test(function(t) {
+    var res = new Response('hello');
+    return res.text().then(function(text) {
+        assert_equals(text, 'hello');
+        return Promise.all([res.text(), res.text()]);
+      }).then(function(texts) {
+        assert_equals(texts[0], '');
+        assert_equals(texts[1], '');
+        return res.body.getReader().read();
+      }).then(function(r) {
+        assert_true(r.done);
+        assert_equals(r.value, undefined);
+      });
+  }, 'Read after text()');
+
 done();