RFR: 8287555: Tighten G1 G1BlockOffsetTable::block_start() code [v2]

[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 incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Cleanup
 - 828755:5 Tighten G1BlockOffsetTable::block_start() code
   
   initial version
 - Make block_start_reaching_into_card() const
 - initial version

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9059/files
  - new: https://git.openjdk.org/jdk/pull/9059/files/04b720b6..ac2740c9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9059&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9059&range=00-01

  Stats: 92000 lines in 1801 files changed: 58028 ins; 18494 del; 15478 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