RFR: 8314951: VM build without C2 still fails after JDK-8313530

[Jie Fu]

JDK-8313530 fixed the release VM build but the debug VM build would still fail.
This patch fix the debug VM build failure.
Thanks.

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Commit messages:
 - 8314951: VM build without C2 still fails after JDK-8313530

Changes: https://git.openjdk.org/jdk/pull/15419/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15419&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314951
  Stats: 4 lines in 1 file changed: 4 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15419.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15419/head:pull/15419

PR: https://git.openjdk.org/jdk/pull/15419