Auto merge of #13356 - jeenalee:mozmap-headers, r=jdm

Support OpenEndedDictionary (Mozmap) in the Headers

<!-- Please describe your changes on the following line: -->

This PR will support OpenEndedDictionary (based on MozMap implementation from #13332) in the Headers API.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #11897  (github issue number if applicable).

<!-- Either: -->
- [X] There are tests for these changes OR
- [ ] These changes do not require tests because _____

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/13356)
<!-- Reviewable:end -->

tests/wpt/metadata/fetch/api/headers/headers-basic.html.ini

@@ -1,35 +0,0 @@
-[headers-basic.html]
-  type: testharness
-  [Create headers from empty object]
-    expected: FAIL
-
-  [Create headers with OpenEndedDictionary]
-    expected: FAIL
-
-  [Create headers with existing headers]
-    expected: FAIL
-
-  [Check has method]
-    expected: FAIL
-
-  [Check delete method]
-    expected: FAIL
-
-  [Check get method]
-    expected: FAIL
-
-  [Check keys method]
-    expected: FAIL
-
-  [Check values method]
-    expected: FAIL
-
-  [Check entries method]
-    expected: FAIL
-
-  [Check Symbol.iterator method]
-    expected: FAIL
-
-  [Check forEach method]
-    expected: FAIL
-

tests/wpt/metadata/fetch/api/headers/headers-casing.html.ini

@@ -1,5 +0,0 @@
-[headers-casing.html]
-  type: testharness
-  [Create headers, names use characters with different case]
-    expected: FAIL
-

tests/wpt/metadata/fetch/api/headers/headers-normalize.html.ini

@@ -1,5 +0,0 @@
-[headers-normalize.html]
-  type: testharness
-  [Create headers with not normalized values]
-    expected: FAIL
-

tests/wpt/metadata/fetch/api/request/request-clone.sub.html.ini

@@ -1,3 +1,8 @@
 [request-clone.sub.html]
   type: testharness
-  expected: ERROR
+  [Check cloning a request]
+    expected: FAIL
+
+  [Check cloning a request copies the headers]
+    expected: FAIL
+

tests/wpt/metadata/fetch/api/request/request-init-002.html.ini

@@ -1,8 +1,5 @@
 [request-init-002.html]
   type: testharness
-  [Initialize Request with headers values]
-    expected: FAIL
-
   [Initialize Request's body with undefined]
     expected: FAIL
 

tests/wpt/metadata/fetch/api/request/request-init-003.sub.html.ini

@@ -1,3 +1,14 @@
 [request-init-003.sub.html]
   type: testharness
-  expected: ERROR
+  [Check request values when initialized from Request]
+    expected: FAIL
+
+  [Check request values when initialized from Request and init values]
+    expected: FAIL
+
+  [Check request values when initialized from url string]
+    expected: FAIL
+
+  [Check request values when initialized from url and init values]
+    expected: FAIL
+

tests/wpt/metadata/fetch/api/request/request-structure.html.ini

@@ -15,9 +15,6 @@
   [Request has text method]
     expected: FAIL
 
-  [Check headers attribute]
-    expected: FAIL
-
   [Check referrer attribute]
     expected: FAIL
 

tests/wpt/metadata/fetch/api/response/response-clone.html.ini

@@ -1,3 +1,20 @@
 [response-clone.html]
   type: testharness
-  expected: ERROR
+  [Check Response's clone has the expected attribute values]
+    expected: FAIL
+
+  [Check orginal response's body after cloning]
+    expected: FAIL
+
+  [Check cloned response's body]
+    expected: FAIL
+
+  [Cannot clone a disturbed response]
+    expected: FAIL
+
+  [Cloned responses should provide the same data]
+    expected: FAIL
+
+  [Cancelling stream should not affect cloned one]
+    expected: FAIL
+

tests/wpt/metadata/fetch/api/response/response-init-002.html.ini

@@ -1,8 +1,5 @@
 [response-init-002.html]
   type: testharness
-  [Initialize Response with headers values]
-    expected: FAIL
-
   [Initialize Response's body with application/octet-binary]
     expected: FAIL
 

tests/wpt/metadata/html/dom/interfaces.html.ini

@@ -10664,3 +10664,4 @@
 
   [Navigator interface: window.navigator must inherit property "hardwareConcurrency" with the proper type (22)]
     expected: FAIL
+

tests/wpt/metadata/webgl/conformance-1.0.3/conformance/context/methods.html.ini

@@ -301,3 +301,4 @@
 
   [WebGL test #49: Property either does not exist or is not a function: validateProgram]
     expected: FAIL
+

tests/wpt/metadata/webgl/conformance-1.0.3/conformance/state/gl-enable-enum-test.html.ini

@@ -8,3 +8,4 @@
 
   [WebGL test #85: getError expected: NO_ERROR. Was INVALID_ENUM : there should be no errors]
     expected: FAIL
+