RFR: 8272216: G1: replace G1ParScanThreadState::_dest with a constant [v2]

[Albert Mingkun Yang]

> Simple change of removing an array with statically-known identical elements.
> 
> Test: hotspot_gc

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.java.net/jdk/pull/5065/files
  - new: https://git.openjdk.java.net/jdk/pull/5065/files/a134b432..0e9c8e0d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5065&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5065&range=00-01

  Stats: 3 lines in 1 file changed: 2 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5065.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5065/head:pull/5065

PR: https://git.openjdk.java.net/jdk/pull/5065