Unbeaten Bayer Leverkusen went eight points clear at the top of the Bundesliga on Saturday after a 2-1 win at Heidenheim while four other games in the German top flight were again interrupted by fan protests. Right wingback Jeremie Frimpong netted with his left foot on the break and Amine Adli rounded the goalkeeper to boost Leverkusen ahead of second-placed Bayern Munich going to Bochum on Sunday. The win was a 32nd game unbeaten in all competitions, equalling an old German record held by Bayern. “It’s a very important win for us,” coach Xabi Alonso told a news conference. “Winning here is ne…