Move FreeBSD deps install to common CI script

Making the OS filter in test driver consistent as per
https://github.com/gbdev/rgbds/pull/1899#discussion_r2942998932

.github/scripts/install_deps.sh

@@ -1,5 +1,6 @@
-#!/usr/bin/env bash
-set -euo pipefail
+#!/bin/sh
+# This script requires `sh` instead of `bash` because the latter is not always installed on FreeBSD.
+set -eu
 
 case "${1%-*}" in
 	ubuntu)
@@ -13,6 +14,9 @@ case "${1%-*}" in
 		export PATH="/opt/homebrew/opt/bison/bin:$PATH"
 		printf 'PATH=%s\n' "$PATH" >>"$GITHUB_ENV" # Make it available to later CI steps too
 		;;
+	freebsd)
+		pkg install -y bash bison cmake git png
+		;;
 	*)
 		echo "WARNING: Cannot install deps for OS '$1'"
 		;;

.github/workflows/testing.yml

@@ -376,14 +376,9 @@ jobs:
           release: "14.3"
           usesh: true
           prepare: |
-            pkg install -y \
-              bash \
-              bison \
-              cmake \
-              git \
-              png
+            .github/scripts/install_deps.sh freebsd
           run: | # FreeBSD `c++` compiler does not support `make develop` sanitizers ASan or UBSan
-            cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_COMPILER=c++ -DUSE_EXTERNAL_TESTS=OFF -DTESTS_OS_NAME=bsd
+            cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_COMPILER=c++ -DUSE_EXTERNAL_TESTS=OFF -DTESTS_OS_NAME=freebsd
             cmake --build build -j4 --verbose
             cmake --install build --verbose
             cmake --build build --target test

test/run-tests.sh

@@ -138,6 +138,6 @@ test_downstream LIJI32    SameBoy bootroms build/bin/BootROMs/cgb_boot.bin 11390
 # gb-starter kit fails with any `make` on Windows: https://codeberg.org/ISSOtm/gb-starter-kit/issues/1
 # gb-starter-kit fails with macOS/BSD `make`: https://codeberg.org/ISSOtm/gb-starter-kit/issues/29
 case "${osname%%-*}" in
-	windows | macos | bsd) ;;
+	windows | macos | *bsd) ;;
 	*) test_downstream ISSOtm gb-starter-kit all bin/boilerplate.gb b4f130169ba73284e0d0e71b53e7baa4eca2f7fe;;
 esac