RFR: 8357693: AOTCodeCompressedOopsTest.java failed with -XX:+UseLargePages

[Ioi Lam]

With `-XX:+UseLargePages`, memory mapping may fail on some OSes if the size is not large page aligned, so let's use `read()` instead.

With this fix, the test cases passes.

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Commit messages:
 - 8357693: AOTCodeCompressedOopsTest.java failed with -XX:+UseLargePages

Changes: https://git.openjdk.org/jdk/pull/25508/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25508&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8357693
  Stats: 5 lines in 1 file changed: 3 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/25508.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25508/head:pull/25508

PR: https://git.openjdk.org/jdk/pull/25508