Add additional debug logging for startSurface crashes

Summary:
There are a very, very small number of crashes in production that are hitting this line. I would like to understand what the existing tag ID is (perhaps it's eqal to the ID being set, which would indicate "double-start"). If not, it indicates that fragments are being reused somewhere, or something else odd is going on with lifecycles.

Changelog: [Internal]

Reviewed By: ejanzer

Differential Revision: D24953785

fbshipit-source-id: 079c86cdb571749662cca46feeaebdd6cb1281f4

ReactAndroid/src/main/java/com/facebook/react/fabric/mounting/MountingManager.java

@@ -103,6 +103,11 @@ public class MountingManager {
   @ThreadConfined(UI)
   public void addRootView(int reactRootTag, @NonNull View rootView) {
     if (rootView.getId() != View.NO_ID) {
+      FLog.e(
+          TAG,
+          "Trying to add RootTag to RootView that already has a tag: existing tag: [%d] new tag: [%d]",
+          rootView.getId(),
+          reactRootTag);
       throw new IllegalViewOperationException(
           "Trying to add a root view with an explicit id already set. React Native uses "
               + "the id field to track react tags and will overwrite this field. If that is fine, "