RFR: 8296155: Simplify CDS heap region address calculation [v3]

[Ioi Lam]

> Rewrite and simplify the convoluted logic used to calculate the runtime location of a CDS heap region. Now it's as simple as:
> 
> 
> FileMapRegion::dumptime_base() + ArchiveHeapLoader::runtime_delta();
> 
> 
> See `FileMapInfo::heap_region_runtime_start_address` for an example.
> 
> Also removed dead code:
> 
> - `FileMapInfo::is_in_shared_region`
> - `MetaspaceShared::is_in_shared_region`
> - `FileMapInfo::stop_sharing_and_unmap`

Ioi Lam has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:

 - Merge branch 'master' into 8296155-simplify-cds-heap-region-address-calc
 - updated CURRENT_CDS_ARCHIVE_VERSION to 17
 - Merge branch 'master' into 8296155-simplify-cds-heap-region-address-calc
 - @coleenp comments
 - 8296155: Simplify CDS heap region address calculation

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Changes: https://git.openjdk.org/jdk/pull/10923/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10923&range=02
  Stats: 137 lines in 7 files changed: 23 ins; 97 del; 17 mod
  Patch: https://git.openjdk.org/jdk/pull/10923.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10923/head:pull/10923

PR: https://git.openjdk.org/jdk/pull/10923