[jdk16u] RFR: 8258243: C2: assert failed ("Bad derived pointer") with -XX:+VerifyRegisterAllocator

[Tobias Hartmann]

Backport of [JDK-8258243](https://bugs.openjdk.java.net/browse/JDK-8258243). Applies cleanly.

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Commit messages:
 - 8258243: C2: assert failed ("Bad derived pointer") with -XX:+VerifyRegisterAllocator

Changes: https://git.openjdk.java.net/jdk16u/pull/10/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk16u&pr=10&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8258243
  Stats: 43 lines in 2 files changed: 40 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk16u/pull/10.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16u pull/10/head:pull/10

PR: https://git.openjdk.java.net/jdk16u/pull/10