jsgen: tests: ensure output deletion on fail (#6875)

vlib/v/gen/js/jsgen_test.v

@@ -6,25 +6,23 @@ const (
 	v_options  = '-b js -w'
 )
 
+fn testsuite_end() {
+	os.rmdir_all(output_dir)
+}
+
 fn test_example_compilation() {
 	vexe := os.getenv('VEXE')
 	os.chdir(os.dir(vexe))
-
 	os.mkdir_all(output_dir)
-
 	files := find_test_files()
 	for file in files {
 		path := os.join_path(test_dir, file)
 		println('Testing $file')
-
 		v_code := os.system('$vexe $v_options -o ${output_dir}${file}.js $path')
 		if v_code != 0 { assert false } // Compilation failed
-
 		js_code := os.system('node ${output_dir}${file}.js')
 		if js_code != 0 { assert false } // Running failed
 	}
-
-	os.rmdir_all(output_dir)
 }
 
 fn find_test_files() []string {