 Bug in read_csv and read_excel not applying dtype to second col with dup cols
- [x] closes #35211
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [x] whatsnew entry

FYI this breaks parsing with a non-dict dtype. Could you provide an example? Documentation for read_csv says dtype may be "a type name _or_ dict".
`pandas.read_csv("test.csv", engine="python", dtype="str")` and `pandas.read_csv("test.csv", engine="python", dtype=str)` now error because this code's new calls to .get assume a dict.  Your test file has duplicate columns too? Will look into this later  > Your test file has duplicate columns too? Will look into this later

Indeed it does, good eye. That's the unfortunate reality when non-programmer people make documents.

Here's my test file:
[test.csv](https://github.com/pandas-dev/pandas/files/6657781/test.csv)

But of course
```
A,B,B
1,1,1
```
shows it too. I should have filed an issue first. I've done that now: https://github.com/pandas-dev/pandas/issues/42022