RFR: 8329417: Remove objects with no pointers from relocation bitmap [v4]

[Matias Saavedra Silva]

> Both the read-write and read-only regions of the relocation bitmap contain metaspace objects with no pointers which do not need to be relocated. By sorting the maps, objects with no pointers can bubble to the top and the bitmap can trim the "leading zeros" thus reducing the archive size and reducing the number of pages. Verified with tier 1-5 tests.

Matias Saavedra Silva has updated the pull request incrementally with one additional commit since the last revision:

  Ioi comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18803/files
  - new: https://git.openjdk.org/jdk/pull/18803/files/be144f64..29e367bb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18803&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18803&range=02-03

  Stats: 15 lines in 3 files changed: 7 ins; 1 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/18803.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18803/head:pull/18803

PR: https://git.openjdk.org/jdk/pull/18803