BRUSSELS — Brussels is about to show some love to a group of companies it has ignored for years. Europe has no shortage of promising tech pioneers, but these companies are failing to scale across the EU and keep up with their U.S. and Chinese peers as they grapple with fragmentation across the 27-nation bloc in corporate law, taxation and employment. Though some startup groups are split on whether it’s likely to work, the European Commission will on Wednesday unveil a sweeping proposal, dubbed