[lworld] RFR: 8262129: [lworld] C2 compilation fails with assert 'can not use dead node'

[Tobias Hartmann]

We hit an assert with `-XX:++VerifyIterativeGVN` because the hook nodes created by `PhaseMacroExpand::expand_mh_intrinsic_return` are dead. Similar to the mainline fix for [https://bugs.openjdk.java.net/browse/JDK-8238756](JDK-8238756), we have to add an input to these nodes.

Best regards,
Tobias

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Commit messages:
 - 8262129: [lworld] C2 compilation fails with assert 'can not use dead node'

Changes: https://git.openjdk.java.net/valhalla/pull/346/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=346&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262129
  Stats: 9 lines in 1 file changed: 2 ins; 0 del; 7 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/346.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/346/head:pull/346

PR: https://git.openjdk.java.net/valhalla/pull/346