Revert "Enable disallowdocumentaccess"

This reverts commit f86eb723.

Reason for revert: Rolling back for now due to concerns over Service Workers

Original change's description:
> Enable disallowdocumentaccess
>
> Allow the ability to restrict same origin documents.
> Approved intent to ship https://groups.google.com/a/chromium.org/g/blink-dev/c/TzuPAx9ZOk0/m/5num2KNACAAJ
>
> https://chromestatus.com/feature/5648946183536640
>
> BUG=961448
>
> Change-Id: Ic3996eb5015484fd3d3220b357d5b17d50413d60
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2417099
> Reviewed-by: Philip Jägenstedt <foolip@chromium.org>
> Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#809355}

TBR=dtapuska@chromium.org,foolip@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 961448
Change-Id: Idaf3961f6dd1ff3449a75ea1b0a2db6dbb9211a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2514962Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823548}

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -703,7 +703,7 @@
     },
     {
       name: "DisallowDocumentAccess",
-      status: "stable",
+      status: "experimental",
     },
     {
       name: "DisplayCutoutAPI",

third_party/blink/web_tests/virtual/stable/webexposed/element-instance-property-listing-expected.txt

@@ -627,7 +627,6 @@ html element iframe
     property contentDocument
     property contentWindow
     property csp
-    property disallowDocumentAccess
     property featurePolicy
     property frameBorder
     property getSVGDocument

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-expected.txt

@@ -2881,7 +2881,6 @@ interface HTMLIFrameElement : HTMLElement
     getter contentDocument
     getter contentWindow
     getter csp
-    getter disallowDocumentAccess
     getter featurePolicy
     getter frameBorder
     getter height
@@ -2903,7 +2902,6 @@ interface HTMLIFrameElement : HTMLElement
     setter allowFullscreen
     setter allowPaymentRequest
     setter csp
-    setter disallowDocumentAccess
     setter frameBorder
     setter height
     setter loading