Does the Vulkan SPIR-V and API version need to match?

From a review comment, see: https://github.com/KhronosGroup/OpenCL-CTS/pull/2536#pullrequestreview-3362636592

> I don't have a very strong opinion about this, but I think it should be fine to invoke glslang and target the older SPIR-V environment, and it would only be a problem to target a newer SPIR-V environment.
>
> Is a validation layer complaining about a mismatch, or is there something else that prompted this change?

Basically, does the Vulkan SPIR-V version need to match the Vulkan API version? If not, is the PR masking some other issue?

Start with pull request 2536 and the linked review comment, then investigate whether the Vulkan SPIR-V target version must match the Vulkan API version. Determine whether the proposed change is masking another issue and record the compatibility conclusion or required follow-up.

Written by the indexing model from the issue text.