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

[William Kemper]

Clean backport.

-------------

Commit messages:
 - Backport 249f141211c94afcce70d9d536d84e108e07b4e5

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/150/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=150&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/shenandoah-jdk21u/pull/150.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/150/head:pull/150

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/150