[jdk17u-dev] RFR: 8282590: C2: assert(addp->is_AddP() && addp->outcnt() > 0) failed: Don't process dead nodes

[Martin Doerr]

Clean backport of [JDK-8282590](https://bugs.openjdk.java.net/browse/JDK-8282590)

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Commit messages:
 - Backport d29c7e740d51cb50a1aa0a941a5b460782f8da68

Changes: https://git.openjdk.java.net/jdk17u-dev/pull/315/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17u-dev&pr=315&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8282590
  Stats: 39 lines in 3 files changed: 30 ins; 4 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk17u-dev/pull/315.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17u-dev pull/315/head:pull/315

PR: https://git.openjdk.java.net/jdk17u-dev/pull/315