RFR: 8355681: G1HeapRegionManager::find_contiguous_allow_expand ignores free regions when checking regions available for allocation [v2]

[Ivan Walulya]

> Hi,
> 
> Please review this change to account for free regions when checking if we have enough regions to satisfy an allocation request. Currently, we have that a `_hrm.expand_and_allocate_humongous` call fails where an `expand_and_allocate` call succeeds for the same allocation request. 
> 
> Testing: Tier 1-3

Ivan Walulya has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Albert review
 - Merge branch 'master' into 8355681-find_contiguous_allow_expand
 - init

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/24915/files
  - new: https://git.openjdk.org/jdk/pull/24915/files/5e8e4a73..5085e54b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24915&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24915&range=00-01

  Stats: 13278 lines in 385 files changed: 9400 ins; 1696 del; 2182 mod
  Patch: https://git.openjdk.org/jdk/pull/24915.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24915/head:pull/24915

PR: https://git.openjdk.org/jdk/pull/24915