Fix ``build_tests`` target in Makefile build to build tests it should have been building.
Fix ``build_tests`` target in Makefile build to build tests it should
have been building.

psuriana/Halide,kgnk/Halide,psuriana/Halide,dan-tull/Halide,dougkwan/Halide,delcypher/Halide,adasworks/Halide,smxlong/Halide,psuriana/Halide,kenkuang1213/Halide,adasworks/Halide,tdenniston/Halide,mcanthony/Halide,delcypher/Halide,mcanthony/Halide,delcypher/Halide,myrtleTree33/Halide,smxlong/Halide,kgnk/Halide,ronen/Halide,ronen/Halide,dougkwan/Halide,ronen/Halide,kenkuang1213/Halide,delcypher/Halide,dan-tull/Halide,myrtleTree33/Halide,kenkuang1213/Halide,dan-tull/Halide,kgnk/Halide,adasworks/Halide,adasworks/Halide,jiawen/Halide,tdenniston/Halide,jiawen/Halide,ronen/Halide,dougkwan/Halide,ronen/Halide,adasworks/Halide,myrtleTree33/Halide,ronen/Halide,myrtleTree33/Halide,jiawen/Halide,tdenniston/Halide,smxlong/Halide,kgnk/Halide,myrtleTree33/Halide,kenkuang1213/Halide,tdenniston/Halide,smxlong/Halide,psuriana/Halide,mcanthony/Halide,tdenniston/Halide,delcypher/Halide,smxlong/Halide,dan-tull/Halide,mcanthony/Halide,dan-tull/Halide,psuriana/Halide,myrtleTree33/Halide,adasworks/Halide,jiawen/Halide,dan-tull/Halide,kenkuang1213/Halide,mcanthony/Halide,kgnk/Halide,delcypher/Halide,smxlong/Halide,ronen/Halide,adasworks/Halide,kgnk/Halide,psuriana/Halide,myrtleTree33/Halide,tdenniston/Halide,dan-tull/Halide,dougkwan/Halide,tdenniston/Halide,kgnk/Halide,dougkwan/Halide,mcanthony/Halide,jiawen/Halide,mcanthony/Halide,adasworks/Halide,jiawen/Halide,delcypher/Halide,ronen/Halide,dougkwan/Halide,delcypher/Halide,dan-tull/Halide,kenkuang1213/Halide,mcanthony/Halide,smxlong/Halide,psuriana/Halide,jiawen/Halide,kenkuang1213/Halide,kgnk/Halide,smxlong/Halide,kenkuang1213/Halide,dougkwan/Halide,tdenniston/Halide,myrtleTree33/Halide,dougkwan/Halide