check-by-name: Remove legacy CI script

See the removed comment for why it can be removed now

pkgs/test/nixpkgs-check-by-name/scripts/fetch-pinned-tool.sh

@@ -1,34 +0,0 @@
-#!/usr/bin/env bash
-# Legacy script, can be removed once the PR removing its use is merged.
-# It's not used anymore because CI and local runs both use pinned-tool.json as their source of truth now,
-# though in different ways since local runs need to support arbitrary platforms
-
-# Try to not use nix-shell here to avoid fetching Nixpkgs,
-# especially since this is used in CI
-# The only dependency is `jq`, which in CI is implicitly available
-# And when run from ./run-local.sh is provided by that parent script
-
-set -o pipefail -o errexit -o nounset
-
-trace() { echo >&2 "$@"; }
-
-SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
-
-pin_file=$SCRIPT_DIR/pinned-tool.json
-
-if (( $# < 1 )); then
-    trace "Usage: $0 fetch OUTPUT_PATH"
-    trace "OUTPUT_PATH: The output symlink path for the tool"
-    exit 1
-fi
-output=$1
-
-trace "Reading $pin_file.. "
-rev=$(jq -r .rev "$SCRIPT_DIR"/pinned-tool.json)
-trace -e "Git revision is \e[34m$rev\e[0m"
-path=$(jq -r '."ci-path"' "$SCRIPT_DIR"/pinned-tool.json)
-trace "Tooling path is $path"
-
-trace -n "Fetching the prebuilt version of nixpkgs-check-by-name.. "
-nix-store --add-root "$output" -r "$path" >/dev/null
-realpath "$output"