RFR: 8376650: os::release_memory_special may not be needed anymore

[Casper Norrbin]

Hi everyone,

`os::release_memory_special` releases memory backed by explicit (non-THP) large pages on Linux. Its point was to handle the case where explicit large pages were allocated with system V shared memory instead of mmap. Since we removed the use of system V memory with [JDK-8261894](https://bugs.openjdk.org/browse/JDK-8261894), `pd_release_memory_special` was changed to simply forward to `pd_release_memory`. 

With these functions no longer serving a purpose (`os::release_memory_special` effectively just calls `os::release_memory`) I propose we remove them completely and replace uses with calls to `os::release_memory` instead.

Testing:
- Oracle tiers 1-5

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Commit messages:
 - removed release_memory_special

Changes: https://git.openjdk.org/jdk/pull/29880/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29880&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8376650
  Stats: 65 lines in 10 files changed: 0 ins; 53 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/29880.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29880/head:pull/29880

PR: https://git.openjdk.org/jdk/pull/29880