refactor: Remove unused `tmpdir` in tests
🚀 Feature (Refactoring)
tmpdir fixture provided by pytest is used at some places in the tests. However, not all tmpdir references are not actually used.
Example
Below is one example of unnecessary tmpdir.

  
    
      pytorch-lightning/tests/core/test_datamodules.py
    
    
        Lines 104 to 107
      in
      839813e
    
  
  
    

        
          
           def test_base_datamodule(tmpdir): 
        

        
          
               dm = TrialMNISTDataModule() 
        

        
          
               dm.prepare_data() 
        

        
          
               dm.setup() 
        
    
  


I'd be happy to submit a PR once you find it reasonable!