RFR: 8338101: remove old remap assertion in map_or_reserve_memory_aligned after JDK-8338058

[Matthias Baesken]

After [JDK-8338058](https://bugs.openjdk.org/browse/JDK-8338058) by mistake an old assertion remained in map_or_reserve_memory_aligned; this has to be removed.

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Commit messages:
 - JDK-8338101

Changes: https://git.openjdk.org/jdk/pull/20519/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20519&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338101
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20519.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20519/head:pull/20519

PR: https://git.openjdk.org/jdk/pull/20519