DevTools: switch Timeline frontend into buffered mode and remove the corresponding experiment.

LayoutTests/virtual/implsidepainting/inspector/timeline/timeline-decode-resize-expected.txt

Index: LayoutTests/virtual/implsidepainting/inspector/timeline/timeline-decode-resize-expected.txt
diff --git a/LayoutTests/virtual/implsidepainting/inspector/timeline/timeline-decode-resize-expected.txt b/LayoutTests/virtual/implsidepainting/inspector/timeline/timeline-decode-resize-expected.txt
index aac53ba72aab66fc8fc08cc2d6b83272790d3cbe..cdf9557bdb6ad6b6973bbf3da71a1a1de5e82e1d 100644
--- a/LayoutTests/virtual/implsidepainting/inspector/timeline/timeline-decode-resize-expected.txt
+++ b/LayoutTests/virtual/implsidepainting/inspector/timeline/timeline-decode-resize-expected.txt
@@ -25,18 +25,6 @@ DecodeImage Properties:
 }
 DecodeImage Properties:
 {
-    children : <object>
-    data : {
-        backendNodeId : <number>
-        imageType : "ICO"
-        url : .../inspector/timeline/resources/test.ico
-    }
-    endTime : <number>
-    startTime : <number>
-    type : "DecodeImage"
-}
-DecodeImage Properties:
-{
     data : {
         backendNodeId : <number>
         url : .../inspector/timeline/resources/test.jpg
@@ -57,26 +45,4 @@ DecodeImage Properties:
     thread : <string>
     type : "DecodeImage"
 }
-DecodeImage Properties:
-{
-    data : {
-        backendNodeId : <number>
-        url : .../inspector/timeline/resources/test.webp
-    }
-    endTime : <number>
-    startTime : <number>
-    thread : <string>
-    type : "DecodeImage"
-}
-DecodeImage Properties:
-{
-    data : {
-        backendNodeId : <number>
-        url : .../inspector/timeline/resources/big.png
-    }
-    endTime : <number>
-    startTime : <number>
-    thread : <string>
-    type : "DecodeImage"
-}