This reverts commit 85fef1bc.

Reason for revert: This actually seems to break the fucshia_x64 bot:

Exception: Some files were excluded with --exclude-file, but not found in the deps list: lib/libVkLayer_parameter_validation.so, lib/libVkLayer_core_validation.so

See https://analysis.chromium.org/waterfall/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyRAsSDVdmU3VzcGVjdGVkQ0wiMWNocm9taXVtLzk0ODYyNWNjNDE2NmE3NjRkYWM2NTRlNjlmZDA3MGFjMDE3MzNkNTMM

Original change's description:
> Vulkan: Build validation layers with asserts only
> 
> Adding ANGLE to the build includes the validation layers, which are only
> for development. We don't want any development or debugging code to be
> included by default in release builds, so tie building the validation
> layers to enablement of asserts.
> 
> Bug: angleproject:2475
> Test: gn gen out/fuchsia_rel --args='target_os="fuchsia" is_debug=false use_goma=true'
>   gn desc out/fuchsia_rel //fuchsia/engine:web_engine runtime_deps
> 
> Change-Id: I6d195c680255dcbc81e95f8e6f80e1e8ace169a2
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1656306
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Commit-Queue: Michael Spang <spang@chromium.org>

TBR=spang@chromium.org,geofflang@chromium.org,jmadill@chromium.org

Change-Id: Ia74efcce2b3dda02dc0c0d292bdeb5ea7c5c3530
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: angleproject:2475
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1657711Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>