[11u] RFR 8252090: JFR: StreamWriterHost::write_unbuffered() stucks in an infinite loop OpenJDK (build 13.0.1+9)

[Jaroslav Bachorík]

Hello,

Can I get the following backport reviewed?

JIRA: https://bugs.openjdk.java.net/browse/JDK-8252090
Webrev: http://cr.openjdk.java.net/~jbachorik/8252090/00/webrev/

The backport and the original patch are differing in 1 place only:
- src/hotspot/share/jfr/recorder/repository/jfrChunkWriter.cpp does
not contain write_magic() method and the change needs to be done in
JfrChunkWriter::open() instead

Ran tier1 and jdk_jfr tests successfully.

Thanks,

-JB-