RFR: 8250961: Move Universe::update_heap_info_at_gc to CollectedHeap

[Aditya Mandaleeka]

This is a small refactoring that moves `update_heap_info_at_gc()` and related members to `CollectedHeap`. There should
be no behavioral change.

jdk/hotspot tier1 passed

JBS: https://bugs.openjdk.java.net/browse/JDK-8250961

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Commit messages:
 - 8250961: Move Universe::update_heap_info_at_gc to CollectedHeap

Changes: https://git.openjdk.java.net/jdk/pull/27/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=27&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8250961
  Stats: 46 lines in 12 files changed: 16 ins; 20 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/27.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/27/head:pull/27

PR: https://git.openjdk.java.net/jdk/pull/27