Improve Firefox logging a little more

Summary:
As title. `message` was an empty string but stringifying an NS_ERROR_FAILURE gives a result more like

```
[Exception... "Failure" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: wuxoyuzore.js :: <TOP_LEVEL> :: line 23" data: no]
```

Reviewed By: flarnie

Differential Revision: D5802539

fbshipit-source-id: 197c08cc37ab9e1f873ddc734a00231570d1cbd0

src/component/selection/setDraftEditorSelection.js

@@ -254,6 +254,7 @@ function addFocusToSelection(
     }
 
     // logging to catch bug that is being reported in t18110632
+    const nodeWasFocus = node === selection.focusNode;
     try {
       selection.extend(node, offset);
     } catch (e) {
@@ -274,6 +275,8 @@ function addFocusToSelection(
         extraParams: JSON.stringify(
           {
             activeElementName: activeElement ? activeElement.nodeName : null,
+            nodeIsFocus: node === selection.focusNode,
+            nodeWasFocus: nodeWasFocus,
             selectionRangeCount: selection.rangeCount,
             selectionAnchorNodeName: selection.anchorNode
               ? selection.anchorNode.nodeName
@@ -283,7 +286,7 @@ function addFocusToSelection(
               ? selection.focusNode.nodeName
               : null,
             selectionFocusOffset: selection.focusOffset,
-            message: e ? e.message : null,
+            message: e ? '' + e : null,
             offset: offset,
           },
           null,