Fix newline weirdness on Azure

[mpenkov]

Some of our tests were failing on Azure because of LF/CRLF weirdness once the .gitattributes file was deleted. In the interest of moving things along, I've disabled those tests (look for AZURE in gensim/test/test_*.py).

Ideally, we should make these tests run and pass.

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I have 2 ideas

• apply .gitattribute only for the concrete subset of files that fail azure (replace * with paths). This will definitely fix azure, but I'm not sure does this avoid effect with "modified files" that Gordon described
• "re-checkout" repo in azure with generated .gitattribute in runtime, this definitely avoid Gordon issue, but not sure will azure work with it (.gitattributes works in a pretty strange way for me, looks like this applied on clone, not on local checkout, worth to investigate)

Gordon right: hacks for CI shouldn't affect contributors

Originally posted by @menshikh-iv in #2836 (comment)