[jdk17u] RFR: 8271600: C2: CheckCastPP which should closely follow Allocate is sunk of a loop

[Tobias Hartmann]

Backport of [JDK-8271600](https://bugs.openjdk.java.net/browse/JDK-8271600). Applies cleanly. Approval is pending.

Thanks,
Tobias

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Commit messages:
 - 8271600: C2: CheckCastPP which should closely follow Allocate is sunk of a loop

Changes: https://git.openjdk.java.net/jdk17u/pull/102/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17u&pr=102&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8271600
  Stats: 4 lines in 1 file changed: 4 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk17u/pull/102.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17u pull/102/head:pull/102

PR: https://git.openjdk.java.net/jdk17u/pull/102