This reverts commit 18e99f4a.

Reason for revert: breaks Mac, e.g.
https://ci.chromium.org/ui/p/chromium/builders/ci/mac-arm64-rel-tests/2197/overview

Original change's description:
> Add SearchType to OpenSharedLibraryWithExtension.
>
> This fixes a bug in SystemInfo_vulkan where we were using the
> System search path for the Vulkan loader when we prefer using the
> custom ANGLE loader.
>
> Bug: chromium:1219969
> Change-Id: Iedf0fd11fe9ed8cc020b445ea9e12a7936937361
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2988791
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
> Commit-Queue: Jamie Madill <jmadill@chromium.org>

Bug: chromium:1219969, chromium:1225040, chromium:1226675
Change-Id: I7a7e329181b69b0fb546e5245d8842723077126f
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3006320
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>