Target additional specs in META.yml files (web-platform-tests#26997)

This brings in the following updates to better associate folders with specs:

- document-policy => link to Document Policy spec
- html/cross-origin-embedder-policy => proposal was integrated into HTML spec
- html/cross-origin-opener-policy => proposal was integrated into HTML spec
- installedapps => link to Get Installed Related Apps API
- js => update URL to use tc39.es domain name
- measure-memory => link to Measure Memory API
- native-file-system => link to File System Access
- screen_enumartion => link to Multi-Screen Window Placement spec
- webrtc-extensions => fix broken link
- x-frame-options => target multipage version (consistent with other folders)

document-policy/META.yml

@@ -0,0 +1 @@
+spec: https://wicg.github.io/document-policy/

html/cross-origin-embedder-policy/META.yml

@@ -1,4 +1,4 @@
-spec: https://mikewest.github.io/corpp/
+spec: https://html.spec.whatwg.org/multipage/origin.html#coep
 suggested_reviewers:
   - mikewest
   - jugglinmike

html/cross-origin-opener-policy/META.yml

@@ -1,4 +1,4 @@
-spec: https://gist.github.com/annevk/6f2dd8c79c77123f39797f6bdac43f3e
+spec: https://html.spec.whatwg.org/multipage/origin.html#cross-origin-opener-policies
 suggested_reviewers:
   - mikewest
   - jugglinmike

installedapp/META.yml

@@ -0,0 +1 @@
+spec: https://wicg.github.io/get-installed-related-apps/spec/

js/META.yml

@@ -1,3 +1,3 @@
-spec: https://tc39.github.io/ecma262/
+spec: https://tc39.es/ecma262/
 suggested_reviewers:
   - Ms2ger

measure-memory/META.yml

@@ -1,2 +1,3 @@
+spec: https://wicg.github.io/performance-measure-memory/
 suggested_reviewers:
   - ulan

native-file-system/META.yml

@@ -0,0 +1 @@
+spec: https://wicg.github.io/file-system-access/

screen_enumeration/META.yml

@@ -0,0 +1 @@
+spec: https://webscreens.github.io/window-placement/

webrtc-extensions/META.yml

@@ -1,3 +1,3 @@
-spec: https://henbos.github.io/webrtc-extensions/
+spec: https://w3c.github.io/webrtc-extensions/
 suggested_reviewers:
   - hbos

x-frame-options/META.yml

@@ -1,4 +1,4 @@
-spec: https://html.spec.whatwg.org/#the-x-frame-options-header
+spec: https://html.spec.whatwg.org/multipage/browsing-the-web.html#the-x-frame-options-header
 suggested_reviewers:
   - annevk
   - mikewest