RFR: 8273659: Replay compilation crashes with SIGSEGV

[Roland Westrelin]

I noticed replay fails when it encounters classes that it can't
resolve (when running with -XX:+ReplayIgnoreInitErrors).

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Commit messages:
 - replay fix

Changes: https://git.openjdk.java.net/jdk/pull/5490/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5490&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273659
  Stats: 6 lines in 1 file changed: 6 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5490.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5490/head:pull/5490

PR: https://git.openjdk.java.net/jdk/pull/5490