[jdk16u] RFR: 8259339: AllocateUninitializedArray C2 intrinsic fails with void.class input

[Tobias Hartmann]

Backport of [JDK-8259339](https://bugs.openjdk.java.net/browse/JDK-8259339). Applies cleanly.

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Commit messages:
 - 8259339: AllocateUninitializedArray C2 intrinsic fails with void.class input

Changes: https://git.openjdk.java.net/jdk16u/pull/16/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk16u&pr=16&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259339
  Stats: 20 lines in 2 files changed: 16 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk16u/pull/16.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16u pull/16/head:pull/16

PR: https://git.openjdk.java.net/jdk16u/pull/16