[clang] [clang] Fix vectorcall HVA/HFA returns on x86 MSVC ABI (PR #203925)

[via cfe-commits]

graphite-app[bot] wrote:

## How to use the Graphite Merge Queue

Add the label <kbd>FP Bundles</kbd> to this PR to add it to the merge queue.

You must have a Graphite account in order to use the merge queue. Sign up using [this link](https://app.graphite.com/invite/github/llvm?ref=merge-queue-instructions-comment&prId=8093595822).

<h2></h2>
<sub>

An organization admin has enabled the [Graphite Merge Queue](https://graphite.dev/docs/graphite-merge-queue) in this repository.

</sub>

<sub>

Please do not merge from GitHub as this will restart CI on PRs being processed by the merge queue.

</sub>

https://github.com/llvm/llvm-project/pull/203925