Describe the bug
java.lang.NullPointerException: Cannot invoke "org.graalvm.visualvm.jfr.model.JFRThread.getId()" because "thread" is null

To Reproduce
Steps to reproduce the behavior:

1. Open unzip and open attached jdk15.jfr
   jdk15.zip
2. Go to Threads tab
3. NPE is thrown to console, see log file.
   logfile.txt