Vulkan: Don't wait for vkAcquireNextImage fence on non-Windows targets

[cohaereo]

Connections
Related issue #8310

Original implementation #8420

Description
The fence wait was originally added to improve frame pacing on Windows, and should have effectively been a no-op on other platforms. However, on specifically Linux NVIDIA drivers, this causes frequent ~10ms stutters, resulting in major performance degradation.

This PR removes the fence wait on non-Windows targets altogether, improving frame pacing and overall performance for those targets.

Testing
Manually tested

Squash or Rebase?

Rebase

Checklist

• I self-reviewed and fully understand this PR.
• WebGPU implementations built with wgpu may be affected behaviorally.
• Validation and feature gates are in place to confine behavioral changes.
• Tests demonstrate the validation and altered logic works.
• CHANGELOG.md entries for the user-facing effects of this change are present.
• The PR is minimal, and doesn't make sense to land as multiple PRs.
• Commits are logically scoped and individually reviewable.
• The PR description has enough context to understand the motivation and solution implemented.

[inner-daemons]

@cohaereo Do you have benchmarks or anything to prove that this really is beneficial? I don't think this was a problem we were aware existed.

[cohaereo]

I've benchmarked this using mangohud in my own application as well as a few of the wgpu examples:

For the WGPU example i had to disable pre_present_notify to prevent Wayland from throttling the redraw requests to VSync, as the issue isn't really visible in a simple benchmark when VSync is enabled, with nor without the patch:

The occasional 10ms fence spikes appear far less often on vsync than at high framerates, but they can still be noticeable in interactive applications like a game engine.

Additionally, the fix has been tested on other Linux systems with AMD/Adreno GPUs, and I couldn't measure any difference there:

I don't think this was a problem we were aware existed.

According to @cwfitzgerald:

cwfitzgerald — 02/05/2026, 21:22
This should have been basically a no-op on other platforms, but we have had reports about this being worse on various flavors of Linux, so we'd accept a PR limiting it to Windows