RFR: 8287555: Tighten G1 G1BlockOffsetTable::block_start() code [v3]

[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 refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  828755:5 Tighten G1BlockOffsetTable::block_start() code
  
  initial version
  
  Cleanup

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9059/files
  - new: https://git.openjdk.org/jdk/pull/9059/files/ac2740c9..c3866f3f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9059&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9059&range=01-02

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 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