RFR: 8287555: Tighten G1 G1BlockOffsetTable::block_start() code [v8]

[Thomas Schatzl]

> Hi all,
> 
>   can I have reviews for this change that specializes `G1BlockOffsetTablePart::block_size` with a variant used for card aligned addresses including some cleanup of comments? This saves some unnecessary lookup of the block size of the object found as for refinement the start address is always aligned.
> 
> Testing: tier1, gha
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:

 - Remove change
 - Merge branch 'master' into pull/9059
 - Merge branch 'master' into pull/9059
 - Refactoring
 - Improve merge, remove unneeded declarations
 - Merge branch 'master' into pull/9059
 - 828755:5 Tighten G1BlockOffsetTable::block_start() code
   
   initial version
   
   Cleanup
 - Make block_start_reaching_into_card() const
 - initial version

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Changes: https://git.openjdk.org/jdk/pull/9059/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9059&range=07
  Stats: 8 lines in 2 files changed: 7 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9059.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9059/head:pull/9059

PR: https://git.openjdk.org/jdk/pull/9059