Change no_torch_function_mode to StashTorchFunctionModeGuard
As discussed [here](https://github.com/pytorch/pytorch/pull/75965#discussion_r863097966), changes the torch dispatch and torch function RAII guards to have unified names (StashXModeGuard). This also match the [TLS guard](https://github.com/pytorch/pytorch/blob/master/aten/src/ATen/core/PythonFallbackKernel.cpp#L30-L44), called StashTLSOnEntryGuard, that has a similar RAII pattern
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76922
Approved by: https://github.com/ezyang
