Update SelectGPUAPI.cpp for Metal.
Update SelectGPUAPI.cpp for Metal.

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