Remove additional invalid SE references from test files.

We no longer offer search engine definitions for less popular search
engines. These definitions were kept historically for metrics
purposes only, but some tests have since begun relying on these.

This CL removes an "unsupported" portion of the test: *all* prepopulated
engines must be linked to some country.

Bug: b:408050650
Change-Id: I1ac639f9b7de6a3daa35bfdd145cc3fc84cfa82e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6394416
Reviewed-by: Patrick Noland <pnoland@chromium.org>
Reviewed-by: Orin Jaworski <orinj@chromium.org>
Auto-Submit: Tomasz Wiszkowski <ender@google.com>
Cr-Commit-Position: refs/heads/main@{#1437766}