[11u] RFR: 8208677: Move inner metaspace cleaning out of class unloading

[Ekaterina Vergizova]

Hello,
I would like to backport 8208677 to 11u as a prerequisite for 8210422.
8210422 fixes the crash described in 8251945 that is already fixed in 11.0.10-oracle.
The full list of suggested prerequisites is specified in [1].

JBS: https://bugs.openjdk.java.net/browse/JDK-8208677
Original patch: http://hg.openjdk.java.net/jdk/jdk/rev/aa3bfacc912c
Webrev for 11u: https://cr.openjdk.java.net/~apetushkov/8208677/webrev.00/

The patch applies almost cleanly except for the change in src/hotspot/share/code/nmethod.cpp.
It is already included in 11u by 8220718.

Tested with tier1; the full list of backports specified in [1] is tested with full regression.

Thanks,
Ekaterina

[1] https://bugs.openjdk.java.net/browse/JDK-8251945?focusedCommentId=14363860&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14363860