DevTools: fix inspector/console/console-viewport-selection.html flakiness

LayoutTests/inspector/console/console-viewport-selection-expected.txt

Index: LayoutTests/inspector/console/console-viewport-selection-expected.txt
diff --git a/LayoutTests/inspector/console/console-viewport-selection-expected.txt b/LayoutTests/inspector/console/console-viewport-selection-expected.txt
index 9e94f2975a3c5b427b7c7ba587221606f9b8cc53..07d04d58b2022207564021d6a5cfdc2722fc6318 100644
--- a/LayoutTests/inspector/console/console-viewport-selection-expected.txt
+++ b/LayoutTests/inspector/console/console-viewport-selection-expected.txt
@@ -158,13 +158,13 @@ Running: testSelectionSingleLineText
 Selected text:<<<EOL
 ssage
 EOL
-first visible message index: 63   viewport is covered: YES
+first visible message index: 75   viewport is covered: YES
 
 Running: testReversedSelectionSingleLineText
 Selected text:<<<EOL
 ssage
 EOL
-first visible message index: 63   viewport is covered: YES
+first visible message index: 75   viewport is covered: YES
 
 Running: testSelectionMultiLineText
 Selected text:<<<EOL
@@ -172,11 +172,11 @@ age #73 console-viewport-selection.html:9
 Message #74 console-viewport-selection.html:9
 Message
 EOL
-first visible message index: 64   viewport is covered: YES
+first visible message index: 74   viewport is covered: YES
 
 Running: testSimpleVisibleSelection
 anchor = {item: 72, offset: 6}, head = {item: 77, offset: 6}
-first visible message index: 65   viewport is covered: YES
+first visible message index: 72   viewport is covered: YES
 
 Running: testHalfScrollSelectionUp
 anchor = {item: 72, offset: 6}, head = {item: 77, offset: 6}
@@ -208,7 +208,7 @@ first visible message index: 135   viewport is covered: YES
 
 Running: testReversedVisibleSelection
 anchor = {item: 76, offset: 6}, head = {item: 71, offset: 6}
-first visible message index: 64   viewport is covered: YES
+first visible message index: 71   viewport is covered: YES
 
 Running: testShiftClickReversedSelectionOver
 anchor = {item: 76, offset: 6}, head = {item: 10, offset: 0}