Revert "exo: Don't double-free wayland proxies in the fuzzer::Harness"

This reverts commit 3bfe0cef.

Reason for revert: WaylandFuzzerTest.MakeSureItWorks is failing after the CL.

First fail build:
https://ci.chromium.org/ui/p/chromium/builders/ci/Linux%20Chromium%20OS%20ASan%20LSan%20Tests%20%281%29/51338/overview


Original change's description:
> exo: Don't double-free wayland proxies in the fuzzer::Harness
>
> Libwayland frees its proxies when the wl_display disconnects. As such
> the harness was double-freeing those proxies itself.
>
> Bug: b:283629115
> Change-Id: Id87383e20e133d6577adf09c5280b2e17a4598e6
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4549020


> Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
> Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1147898}

Bug: b:283629115
Change-Id: If1e94bebc6166f9a39cf38b3a98c67ebb8f84cb2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4557407


Owners-Override: Owen Min <zmin@chromium.org>
Auto-Submit: Owen Min <zmin@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1148098}