[WIP] Removal of the C++ Runtime files that are not needed

[AlexandreEichenberger]

Removed the unused C++ files in the onnx-mlir/Runtimes subdirectory, edited the CMakelist.txt accordingly.

[AlexandreEichenberger]

@chentong319 would you be able to test this PR in your env, as we don't have too much for the lightweight testing as this time?
Or accept changes and I can fix issues specific to your use case?

[chentong319]

I tested your PR. It got error for tests/helloworld.py.

undefined symbol: OM_DATA_TYPE_SIZE

[AlexandreEichenberger]

@chentong319 thanks, let me look into it.

[chentong319]

By the way, I tried to link cruntime when model.so is loaded and the program can run correctly. That could be an alternative solution. To remove cruntime from the static linked libraries for model.so, we need:

1. change the link command in onnx-mlir, remove cruntime and add -lm.
2. Change CMakeList.txt to build a dynamic lib for cruntime.
3. Change OMPyInfer to load the cruntime from the package.

I am thinking about a separate PR for this change.

[AlexandreEichenberger]

@chentong319 yes, I think we should unlink the cruntime from the model, and build it in the light. Its already the case that the OMTensorUtils contains cruntime in the non-light version; I think for C programs, we should only link the cruntime; for CPP programs, we should only link what we currently call OMExecutionSession(and should be renameOMCppRuntime); and for python we should only link the python version of the execution session, which should in turn load both the cruntime, the OMExecutionSession` plus the python version of it.

In any case, I have re-added the missing constants, so please do a new test please.