[ML] Use TESTED_OBJS dependency in PyTorch unittest makefile

[davidkyle]

Following the changes in #1773 this causes a rebuild of the unit tests when the compiled class files change

[droberts195]

In this case the Windows CI failed, but it did actually run and found an error:

CBufferedIStreamAdapter.obj : error LNK2019: unresolved external symbol __imp_ntohl referenced in function "private: bool __cdecl ml::torch::CBufferedIStreamAdapter::parseSizeFromStream(unsigned __int64 &)" (?parseSizeFromStream@CBufferedIStreamAdapter@torch@ml@@AEAA_NAEA_K@Z)
ml_test.exe : fatal error LNK1120: 1 unresolved externals

So USE_NET=1 needs adding to the Makefile.

[davidkyle]

The build passed on all platforms except macOS ARM as expected

[droberts195]

LGTM