RFR: 8339242: Fix overflow issues in AdlArena

[Casper Norrbin]

Hi everyone,

This PR addresses an issue in `adlArena` where some allocations lack checks for overflow. This could potentially result in successful allocations when called with unrealistic values.

The fix includes:

- Adding assertions to check for potential overflow.
- Reordering some operations to guard against overflow.

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Commit messages:
 - overflow checks in adlArena

Changes: https://git.openjdk.org/jdk/pull/20774/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20774&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339242
  Stats: 9 lines in 2 files changed: 5 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/20774.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20774/head:pull/20774

PR: https://git.openjdk.org/jdk/pull/20774