remove InProcessKernel from top-level kernel.inprocess

avoid circular import

IPython/kernel/inprocess/__init__.py

@@ -1,10 +1,10 b''
 from .channels import (
     InProcessShellChannel,
     InProcessIOPubChannel,
     InProcessStdInChannel,
     InProcessHBChannel,
 )
-from .ipkernel import InProcessKernel
+
 from .client import InProcessKernelClient
 from .manager import InProcessKernelManager
 from .blocking import BlockingInProcessKernelClient