LONDON — Google lost its last bid to overturn a European Union antitrust penalty, after the bloc’s top court ruled against it Tuesday in a case that came with a whopping fine and helped jumpstart an era of intensifying scrutiny for Big Tech companies. The European Union’s top court rejected Google’s appeal against the 2.4 billion euro ($2.7 billion) penalty from the European Commission, the 27-nation bloc’s top antitrust enforcer, for violating antitrust rules with its comparison shopping service. Also Tuesday, Apple lost its challenge against an order to repay 13 billion euros ($14.34 billion) in back taxes to Ireland, after the European Court of Justice issued a separate decision siding with the commission in a case targeting unlawful state aid for global corporations. Both companies have now exhausted their appeals in the cases that date to the previous decade.