Because Tyson Chandler barely has played recently because of a bulging disk in his cervical spine, he was asked yesterday if he believed Kevin Garnett might test his neck to see how it fares. “I don’t know,” Chandler said. “I’m going to test some stuff of his as well.” The Knicks’ invaluable center and defensive stalwart, Chandler sounded in terrific spirits and declared his ailing neck is healthy. He’s set to return after a six-game absence and start tomorrow afternoon at the Garden in Game 1 against Garnett’s Celtics. After playing in each of the season’s first 62 games, Chandler has played in just four of the final 20. The main problem has been the bulging disk. “I feel 100 percent, honestly,” Chandler said. “It’s the best I’ve felt in a long time. Best I’ve felt since I got hurt in Denver [on March 13], honestly.” The Knicks went an impressive 12-4 without Chandler, beating the Celtics twice in that stretch. Nevertheless, Garnett missed those games as well. In the two games Chandler did play against Boston this year, he averaged nine points and 12.5 rebounds. After Chandler initially got hurt against the Nuggets, he missed the next 10 games before returning for four contests. In his final one, an April 7 win over the Thunder in Oklahoma City, Chandler looked terrific, scoring 15 points and blocking two shots. Nevertheless, he also re-injured the disk, forcing him to sit out the rest of the regular season. Though Chandler practiced fully yesterday, he’s aware simulating the physicality of a game is difficult to do in practice. But Chandler said he knows what’s coming — and he knows he can take it.