Error in the tests

[LeoLai930603]

I think this line will not get passed, because there is an assertion in functional::matmul which requires the first operand has dim == 2

https://github.com/Kaffaljidhmah2/DeepLearningFramework/blob/a6248bed313164063785657fcf259eca2cc43d0a/src/test.cpp#L170

[Kaffaljidhmah2]

Yeah, you are right. There is a lot of room for improvement. I stopped to maintain this repo after I could use it to do MNIST.