RFR: 8289093: BlockLocationPrinter fails to decode addresses with G1

[Thomas Schatzl]

Hi all,

  can I have reviews for this change that fixes an assertion failure when trying to add annotations to the hs_err file?

The `block_start` API from `CollectedHeap` assumes that useful values for all given addresses is returned, not asserting/crashing like some method deeper in the call chain does since [JDK-8270540](https://bugs.openjdk.org/browse/JDK-8270540), resulting in somewhat scrambled hs_err files and additional stack frames to look at in the debugger. 

Testing: local compilation, gha, tier1-3

Thanks,
  Thomas

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Commit messages:
 - Return the original value for addresses > top in G1CollectedHeap::block_start instead of crashing

Changes: https://git.openjdk.org/jdk19/pull/68/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk19&pr=68&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8289093
  Stats: 6 lines in 1 file changed: 6 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk19/pull/68.diff
  Fetch: git fetch https://git.openjdk.org/jdk19 pull/68/head:pull/68

PR: https://git.openjdk.org/jdk19/pull/68