Fix test

Author: acozzette

js/private/test/js_run_binary/BUILD.bazel

@@ -102,6 +102,7 @@ js_run_binary(
     name = "gen_target_os",
     srcs = [":os_name.txt"],
     args = ["$(rootpath :os_name.txt)"],
+    hoist_runfiles_to_exec_cfg = True,
     stdout = "target_os.txt",
     tags = ["manual"],
     tool = ":read_file",