RFR: 8333099: Missing check for is_LoadVector in StoreNode::Identity

[Christian Hagedorn]

On Wed, 29 May 2024 08:54:35 GMT, Damon Fenacci <dfenacci at openjdk.org> wrote:

> [JDK-8325520](https://bugs.openjdk.org/browse/JDK-8325520) introduced a check for type equality in `StoreNode::Identity` in the specific case of a load vector followed by a store vector.
> Unfortunately the memory node operand might actually not be of type `LoadVector`. So, before retrieving its type, a check for `is_LoadVector` is necessary.

Looks good! Can you also add a regression test?

-------------

Marked as reviewed by chagedorn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/19449#pullrequestreview-2084803593