Add fences between command pool resets. Fix for #3625

[atkurtul]

Fixes #3625 PR checklist:

• [ ] make succeeds (on *nix)
• [x] make reftests succeeds
• [x] tested examples with the following backends: Vulkan

[bors[bot]]

Build succeeded:

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• MacOS Stable
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• Ubuntu Stable
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• Windows Stable