RFR: 8329771: G1: Refactor G1BlockOffsetTable::verify [v2]

[Guoxiong Li]

> Hi all,
> 
> This patch verifies the BOT after writing the BOT and changes the method name for consistence, just like `SerialBlockOffsetTable::verify_for_block` and `ObjectStartArray::verify_for_block`.
> 
> The test `make test-tier1_gc` passed locally. Thanks for taking the time to review.
> 
> Best Regards,
> -- Guoxiong

Guoxiong Li 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:

 - Extract a common method.
 - Move into ASSERT block.
 - Merge branch 'master' into REFACTOR_VERIFY
 - JDK-8329771

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/18711/files
  - new: https://git.openjdk.org/jdk/pull/18711/files/343e43b3..bb2a9c6b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18711&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18711&range=00-01

  Stats: 6335 lines in 232 files changed: 2600 ins; 1602 del; 2133 mod
  Patch: https://git.openjdk.org/jdk/pull/18711.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18711/head:pull/18711

PR: https://git.openjdk.org/jdk/pull/18711