RFR: 8327172: C2 SuperWord: data node in loop has no input in loop: replace assert with bailout

[Emanuel Peter]

This is a regression fix from https://github.com/openjdk/jdk/pull/17657.

I had never encountered an example where a data node in the loop body did not have any input node in the loop.
My assumption was that this should never happen, such a node should move out of the loop itself.

I now encountered such an example. But I think it shows that there are cases where we compute the ctrl wrong.

https://github.com/openjdk/jdk/blob/8835f786b8dc7db1ebff07bbb3dbb61a6c42f6c8/test/hotspot/jtreg/compiler/loopopts/superword/TestNoInputInLoop.java#L65-L73

I now had a few options:
1. Revert to the code before https://github.com/openjdk/jdk/pull/17657: handle such cases with the extra `data_entry` logic. But this would just be extra complexity for patterns that shoud not exist in the first place.
2. Fix the computation of ctrl. But we know that there are many edge cases that are currently wrong, and I am working on verification and fixing these issues in https://github.com/openjdk/jdk/pull/16558. So I would rather fix those pre-existing issues separately.
3. Just create a silent bailout from vectorization, with `VStatus::make_failure`.

I chose option 3, since it allows simple logic, and only prevents vectorization in cases that are already otherwise broken.

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Commit messages:
 - the fix
 - 8327172

Changes: https://git.openjdk.org/jdk/pull/18123/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18123&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327172
  Stats: 103 lines in 3 files changed: 100 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/18123.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18123/head:pull/18123

PR: https://git.openjdk.org/jdk/pull/18123