RFR: 8255131: G1CollectedHeap::is_in() returns wrong result

[Thomas Schatzl]

Hi all,

  please review this change to exchange the broken G1CollectedHeap::is_in() by G1CollectedHeap::is_in_exact() that has the same performance profile and correct.

G1CollectedHeap::is_in() returns true for any region ever committed (and crashes for not yet committed regions), while is_in_exact() (almost) did the right thing. Almost because HeapRegionManager::is_available() would assert if the given pointer is outside the heap and it's not guarded by is_in_reserved.

Test: tier1

Thanks,
  Thomas

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.java.net/jdk/pull/799/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=799&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255131
  Stats: 25 lines in 5 files changed: 0 ins; 20 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/799.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/799/head:pull/799

PR: https://git.openjdk.java.net/jdk/pull/799