DevTools: excessive dumping for jump-to-previous-position.html test

LayoutTests/inspector/jump-to-previous-editing-location.html

Index: LayoutTests/inspector/jump-to-previous-editing-location.html
diff --git a/LayoutTests/inspector/jump-to-previous-editing-location.html b/LayoutTests/inspector/jump-to-previous-editing-location.html
index 2fbd279c225f72c92d7d5154826816c664770ee1..e041dc501c490b8123105217774b063f956ab940 100644
--- a/LayoutTests/inspector/jump-to-previous-editing-location.html
+++ b/LayoutTests/inspector/jump-to-previous-editing-location.html
@@ -177,6 +177,20 @@ function test()
 
         function testHistoryDepth(next)
         {
+            function dumpSimpleHistoryManagerState(title)
+            {
+                var simpleHistoryManager = historyManager._historyManager;
+                var entries = simpleHistoryManager._entries;
+                InspectorTest.addResult("=== SimpleHistoryManager state " + title + " ===");
+                InspectorTest.addResult("entries count: " + entries.length);
+                for (var i = entries.length - 1; i >= 0; --i) {
+                    var position = entries[i]._positionHandle.resolve();
+                    var positionText = position ? "{line: " + position.lineNumber + ", column: " + position.columnNumber + "}" : position + "";
+                    var positionMarker = simpleHistoryManager._activeEntryIndex === i ? ">" : " ";
+                    InspectorTest.addResult(positionMarker + "entry[" + i + "] = " + positionText);
+                }
+                InspectorTest.addResult("=== ===");
+            }
             var lines = [];
             var columns = [];
             const jumpsAmount = WebInspector.EditingLocationHistoryManager.HistoryDepth;
@@ -185,8 +199,17 @@ function test()
                 columns.push(7);
             }
             var editor = panel.visibleView.textEditor;
+            //FIXME(lushnikov): here and below excessive dumping to figure out a reason for
+            // unreproducible bot failures.
+            dumpSimpleHistoryManagerState("before filling history stack");
             clickAndDump(editor, lines, columns);
-            for (var i = 0; i < jumpsAmount; ++i) {
+            dumpSimpleHistoryManagerState("after filling history stack");
+
+            InspectorTest.addResult("First rollback result: " + historyManager._historyManager.rollback());
+            dumpSimpleHistoryManagerState("after first rollback");
+            dumpSelection(editor, "Rolled back");
+
+            for (var i = 0; i < jumpsAmount - 1; ++i) {
                 rollback();
                 dumpSelection(editor, "Rolled back");
             }