Fix metal runtime assertion failures. The latest Metal only permits calling MTLBuffer::didModifyRange and MTLResource::synchronizeResource for buffers with storageMode of MTLStorageModeManaged.
Fix metal runtime assertion failures.
The latest Metal only permits calling MTLBuffer::didModifyRange and
MTLResource::synchronizeResource for buffers with storageMode of
MTLStorageModeManaged.

Former-commit-id: 34b590c8ceacf0721fb3272896a54d893713f1b2
darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide