Remove useless cuda_limit.py

In the previous version of cuda kernel, we use malloc in kernel, which is not
used any more, so remove the heap size setting.

Author: hzhangxyz

qmb/__main__.py

@@ -5,7 +5,6 @@
 """
 
 import tyro
-from . import cuda_limit as _  # type: ignore[no-redef]
 from . import openfermion as _  # type: ignore[no-redef]
 from . import fcidump as _  # type: ignore[no-redef]
 from . import ising as _  # type: ignore[no-redef]