Remove a wtf log from notifyDexLoad.

We added a wtf log to verify an assumption we made when we were
developing ART Service. Now it has been years and we haven't seen this
log being reported, so we can reach the conclusion that our assumption
has been verified and we can remove this log.

Bug: 258223472
Bug: 6527146
Test: Presubmit
Flag: EXEMPT cleanup
Change-Id: I9be98ac06040502c392563758d6e5d6d5bc3d943