Catch up to llvm r239858, where parseBitCodeFile started to return unique_ptr
Catch up to llvm r239858, where parseBitCodeFile started to return unique_ptr


Former-commit-id: 6660a01eedc49274dd938ca96fa67446bec2604e
darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide