Using a local reference ensure that the Status object cannot be disposed before the Dispose. This way it's also possible to use an external Status instance instead of the static one, if needed.

In multithreading .NET 4.8 applications, sometimes in Session finalizer the method c_api.TF_DeleteSession find f.Status static instance already disposed for some reason. No problem for .NET 6 application or with a single thread.

2. 修正一个缺少参数处理的bug

In TF ByteString is more of a byte buffer than valid utf8. Reading it as a String adds escape characters to non-valid utf8. Then converting it to utf16 causes separate issues. Going from ByteString to byte[] fixes both of these.

- Separated multithreading related methods to classname.threading.cs partial file
- ops: Added enforce_singlethreading(), enforce_multithreading()

- Ignored all unit tests related to CSession as it does not use TF.NET's api directly and unable to be tested with other tests parallely.

TensorTest: Added Unit tests for more coverage, reformatted file.
c_api.tensor: Added overloads for TF_NewTensor that does not have deallocator parameters.
BaseSession: Removed disposal immediately after TF_SessionRun call.
c_api.DeallocatorArgs: Added DeallocatorArgs.Empty