RFR: 8373941: Epsilon: Robust counter updates in early VM phases

[Aleksey Shipilev]

See more details in the bug. This PR makes the counters updated on allocation path more robust. New regression test captures the original failure (intermittently). This would be also backported to JDK 26.

Additional testing:
 - [x] Linux x86_64 server fastdebug, `gc/epsilon`, 100x
 - [x] Linux x86_64 server fastdebug, `runtime/cds/appcds/TestEpsilonGCWithCDS.java`, 100x
 - [x] Linux x86_64 server fastdebug, `gc/epsilon/TestInitAllocs.java`, 1000x

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Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/29061/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29061&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373941
  Stats: 107 lines in 5 files changed: 94 ins; 1 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/29061.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29061/head:pull/29061

PR: https://git.openjdk.org/jdk/pull/29061