RFR: 8273414: ResourceObj::operator delete should handle nullptr in debug builds

[Leo Korinth]

This is how delete usually works, This is also how FreeHeap and CHeapObj::operator delete works. Delete does handle nullptr in release builds, it is the assert that may crash. Also, as a user it is nice to call delete without first checking the argument for nullptr.

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Commit messages:
 - 8273414: ResourceObj::operator delete should handle nullptr in debug builds

Changes: https://git.openjdk.java.net/jdk/pull/5385/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5385&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273414
  Stats: 3 lines in 1 file changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5385.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5385/head:pull/5385

PR: https://git.openjdk.java.net/jdk/pull/5385