China’s semiconductor equipment industry is heading into the first-half earnings season under intense scrutiny, as a broad stock rally turns one of the tech sector’s least visible niches into a crowded investor trade. The rally has swept across makers of etching, thin-film deposition, cleaning and testing machines, among others, reflecting bets that China’s next round of chip spending will benefit a wider group of domestic suppliers. Shares of Naura Technology Group have soared more than 70 per...