Assert a command (built with program and args) stderr string is equal to an expression.
let program = "bin/printf-stderr"; let args = ["%s", "hello"]; let s = String::from("hello"); assert_program_args_stderr_eq_expr!(&program, &args, s);
assert_program_args_stderr_eq_expr
assert_program_args_stderr_eq_expr_as_result
debug_assert_program_args_stderr_eq_expr