RFR: 8346737: GenShen: Generational memory pools should not report zero for maximum capacity

[William Kemper]

The following tests fail in generational mode because the old generation reports a _maximum_ capacity of zero when it is empty. It makes sense to treat maximum capacity as a _theoretical_ maximum and let it equal the total size of the heap.

- vmTestbase/nsk/monitoring/MemoryPoolMBean/isCollectionUsageThresholdExceeded/isexceeded001/TestDescription.java 
- vmTestbase/nsk/monitoring/MemoryPoolMBean/isCollectionUsageThresholdExceeded/isexceeded002/TestDescription.java 
- vmTestbase/nsk/monitoring/MemoryPoolMBean/isCollectionUsageThresholdExceeded/isexceeded003/TestDescription.java 
- vmTestbase/nsk/monitoring/MemoryPoolMBean/isCollectionUsageThresholdExceeded/isexceeded004/TestDescription.java 
- vmTestbase/nsk/monitoring/MemoryPoolMBean/isCollectionUsageThresholdExceeded/isexceeded005/TestDescription.java 
- vmTestbase/nsk/monitoring/MemoryPoolMBean/setCollectionUsageThreshold/setthreshold001/TestDescription.java 
- vmTestbase/nsk/monitoring/MemoryPoolMBean/setCollectionUsageThreshold/setthreshold002/TestDescription.java 
- vmTestbase/nsk/monitoring/MemoryPoolMBean/setCollectionUsageThreshold/setthreshold003/TestDescription.java 
- vmTestbase/nsk/monitoring/MemoryPoolMBean/setCollectionUsageThreshold/setthreshold004/TestDescription.java 
- vmTestbase/nsk/monitoring/MemoryPoolMBean/setCollectionUsageThreshold/setthreshold005/TestDescription.java

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Commit messages:
 - Fix usage report log message for non-generational modes

Changes: https://git.openjdk.org/jdk/pull/22851/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22851&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8346737
  Stats: 6 lines in 2 files changed: 0 ins; 6 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/22851.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22851/head:pull/22851

PR: https://git.openjdk.org/jdk/pull/22851