RFR: 8256485: Zero VM build broken after JDK-8254231

[Jorn Vernee]

JDK-8254231 breaks the Zero VM build. This PR contains fixes to get it working again.

Testing: Building zero VM variant on Linux.

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Commit messages:
 - Make zero VM build work

Changes: https://git.openjdk.java.net/jdk/pull/1265/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1265&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256485
  Stats: 135 lines in 8 files changed: 135 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1265.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1265/head:pull/1265

PR: https://git.openjdk.java.net/jdk/pull/1265