RFR: 8256181: Remove Allocation of old generation on alternate memory devices functionality

[Thomas Schatzl]

Hi all,

  can I get reviews for this change that removes the "Allocation of old generation of Java heap on alternate memory devices" functionality introduced with JDK 12 with [JDK-8202286](https://bugs.openjdk.java.net/browse/JDK-8202286) due to being

- not used by anyone
- not maintained by anyone, i.e. several bugs open for a long time and bit rotting
- requiring some workarounds for new feature development wrt to heap management

All flags covered by this feature were experimental flags, so there are no additional procedural issues to take.

I tried to remove all but a few minor cleanups that I thought useful, but of course this is very subjective.

Testing: hs-tier1-5

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Commit messages:
 - Initial import

Changes: https://git.openjdk.java.net/jdk/pull/1162/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1162&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256181
  Stats: 2309 lines in 49 files changed: 4 ins; 2177 del; 128 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1162.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1162/head:pull/1162

PR: https://git.openjdk.java.net/jdk/pull/1162