RFR: 8290826: validate-source failures after JDK-8290016

[Daniel D. Daugherty]

A trivial fix for validate-source failures after JDK-8290016.

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Commit messages:
 - 8290826: validate-source failures after JDK-8290016

Changes: https://git.openjdk.org/jdk/pull/9594/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9594&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290826
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9594.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9594/head:pull/9594

PR: https://git.openjdk.org/jdk/pull/9594