RFR: 6817: AutoBoxing rule can crash due to null dereference

[Marcus Hirt]

Hypothetical solution to hypothetical problem.

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Commit messages:
 - 6817: AutoBoxing rule can crash due to null dereference

Changes: https://git.openjdk.java.net/jmc/pull/286/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=286&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-6817
  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jmc/pull/286.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/286/head:pull/286

PR: https://git.openjdk.java.net/jmc/pull/286