RFR: 8343507: Parallel: Fail if verify_complete finds incorrect states [v2]

[Albert Mingkun Yang]

> Trivial change of replacing `log_warning` with `fatal`, because incorrect `destination_count` always indicate some problem.
> 
> Test: tier1-3

Albert Mingkun Yang has updated the pull request incrementally with one additional commit since the last revision:

  review

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21865/files
  - new: https://git.openjdk.org/jdk/pull/21865/files/f1e2d474..f089f3df

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21865&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21865&range=00-01

  Stats: 8 lines in 1 file changed: 0 ins; 4 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/21865.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21865/head:pull/21865

PR: https://git.openjdk.org/jdk/pull/21865