assertNoMatch = (t, specimen, pattern, message, isUnmatchable, label) => {
  t.throws(() => mustMatch(specimen, pattern), { message }, label);
  if (isUnmatchable) {
    t.throws(() => matches(specimen, pattern), { message }, label);
  } else {
    t.false(matches(specimen, pattern), label);
  }
}
@param {ava.ExecutionContext} t
@param {any} specimen
@param {any} pattern
@param {string} message
@param {boolean} [isUnmatchable]
@param {string} [label]
@returns {void}