RFR: 8375010: C2 VectorAPI: assert(vbox->is_CheckCastPP()) failed: should be expanded [v2]

[Kerem Kat]

> The check `vect->is_Vector() || vect->is_LoadVector()` doesn't handle `Proj` nodes that resolve to vector types, causing an assertion failure when such nodes flow through a `Phi` into `VectorBox`.

Kerem Kat has updated the pull request incrementally with one additional commit since the last revision:

  Simplify expand_vbox_node_helper by merging VectorBox Phi handling

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29200/files
  - new: https://git.openjdk.org/jdk/pull/29200/files/83df3ccf..45b02913

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29200&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29200&range=00-01

  Stats: 30 lines in 1 file changed: 0 ins; 22 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/29200.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29200/head:pull/29200

PR: https://git.openjdk.org/jdk/pull/29200