By Dan Levine SAN FRANCISCO (Reuters) – Four large technology companies should not be allowed to limit evidence about Apple Inc co-founder Steve Jobs at an upcoming trial over no-hire agreements in Silicon Valley, according to a court document filed late on Thursday by employees suing the firms. Tech workers brought a class action lawsuit against Apple, Google Inc, Intel Inc and Adobe Systems Inc in 2011, alleging they conspired to avoid competing for each others employees in order to avert a salary war. The case, which is closely watched in Silicon Valley, is largely built on emails among top executives, including Apples late chief executive Jobs and former Google CEO Eric Schmidt.