CLN: Remove unncessary lambda wrapper
- [ ] closes #xxxx
- [ ] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

A lambda wrapper is unnecessary in these cases as the underlying methods are themselves callable. Moreover, the code does not add any logic in the wrapper to warrant the usage of lambda. 
[jreback] how are these inecessary?
[skasturi]  
- `max` and `lambda x: max(x)` have the exact functionality. 
- `fmt.format` and `lambda x: fmt.format(x)` have the exact functionality

[jreback] did you time the difference
[skasturi] Thank you for suggesting me to do this. They both seem to have the almost similar timing. Guess it's a macro replacement? 

![image](https://user-images.githubusercontent.com/482709/76707024-25542880-66a9-11ea-9f1b-ab84dd95ab4b.png)

[jreback] these are timing using a lambda function
[skasturi] I am not sure what you meant by this. 

[jreback] using max actually transforms this to another operation
[skasturi] Yes. As I mentioned earlier `max` and `fmt.format` are themselves `Callable`. Therefore, in general it might not be necessary to wrap them in a `lambda`. > how are these inecessary?
> [skasturi]
> 
> * `max` and `lambda x: max(x)` have the exact functionality.
> * `fmt.format` and `lambda x: fmt.format(x)` have the exact functionality
> 
> did you time the difference
> [skasturi] Thank you for suggesting me to do this. They both seem to have the almost similar timing. Guess it's a macro replacement?
> 
> these are timing using a lambda function
> [skasturi] I am not sure what you meant by this.
> 
> using max actually transforms this to another operation
> [skasturi] Yes. As I mentioned earlier `max` and `fmt.format` are themselves `Callable`. Therefore, in general it might not be necessary to wrap them in a `lambda`.

show the the asv results Sure. Would you mind telling me how to run the asv_bench? I am unable to find it in the top level readme.  https://pandas.pydata.org/docs/development/contributing.html#running-the-performance-test-suite Thanks for the PR but AFAICT the intent of these benchmarks is to actually measure the application of a lambda function. We should already have measurements for the built-in max function, so I think don't want to do this agree with @WillAyd here, the point of these asv's is to specifically measure when using a lambda. so this change is measuring something else. Thank you @WillAyd and @jreback for the context. 