[11u] RFR: 8231081: TestMetadataRetention fails due to missing symbol id

[Langer, Christoph]

Hi,

as we are about to backport JDK-8225797 [0] - OldObjectSample event creates unexpected amount of checkpoint data - we should also backport JDK-8231081.

This patch did not apply cleanly, I had rejects in the following files:
src/hotspot/share/jfr/recorder/checkpoint/jfrCheckpointManager.cpp
src/hotspot/share/jfr/recorder/checkpoint/types/jfrTypeManager.cpp
src/hotspot/share/jfr/recorder/checkpoint/types/jfrTypeSetUtils.cpp

The first ones were due to the missing ClassDatagraph lock in 11u.

I've resolved them and with the change all jfr related jtreg tests pass, as well as the added testcase.

Bug: https://bugs.openjdk.java.net/browse/JDK-8231081
Original change: https://hg.openjdk.java.net/jdk/jdk/rev/7909763ad193
Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8231081.11u/

Please review.

Thanks
Christoph

[0] https://bugs.openjdk.java.net/browse/JDK-8225797