webrtc: deactivate the rtp-payloadtype WPT

Deactivate the rtp-payloadtype WPT to allow the fix to roll in.
Reactivate the rtp-demuxing WPT.

BUG=None

Change-Id: I776cbc388596a242f376de03747f4cf216d2ca93
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2580806Reviewed-by: Harald Alvestrand <hta@chromium.org>
Commit-Queue: Harald Alvestrand <hta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835162}

third_party/blink/web_tests/TestExpectations

@@ -5767,8 +5767,6 @@ crbug.com/1138591 [ Mac10.15 ] http/tests/dom/raf-throttling-out-of-view-cross-o
 
 # WebRTC: Payload demuxing times out in Plan B. This is expected.
 crbug.com/1139052 virtual/webrtc-wpt-plan-b/external/wpt/webrtc/protocol/rtp-demuxing.html [ Timeout ]
-# WebRTC: allow downstream fix.
-crbug.com/1139052 external/wpt/webrtc/protocol/rtp-demuxing.html [ Pass Failure ]
 
 crbug.com/1137228 [ Mac ] external/wpt/infrastructure/testdriver/click_iframe_crossorigin.sub.html [ Pass Failure ]
 
@@ -5887,3 +5885,6 @@ crbug.com/1156175 external/wpt/requestidlecallback/callback-iframe.html [ Pass T
 
 # Sheriff 2020-12-08
 crbug.com/1154178 external/wpt/webmessaging/broadcastchannel/basics.html [ Pass Failure ]
+
+# WebRTC: allow fix for bugs.webrtc.org/12194 to roll into chrome
+external/wpt/webrtc/protocol/rtp-payloadtypes.html [ Pass Failure ]