remove custom _getsource_func support
@@ -28,5 +28,4 @@ from cupyx.jit._builtin_funcs import shfl_up_sync # NOQA
from cupyx.jit._builtin_funcs import shfl_down_sync # NOQA
from cupyx.jit._builtin_funcs import shfl_xor_sync # NOQA
-_getsource_func = None # NOQA
_n_functions_upperlimit = 100
