Ignore a bunch of temporary files from cmake/ninja.

[kiyolee]

Ignore a bunch of temporary files from cmake/ninja.

[msftclas]

@kiyolee,
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Microsoft Pull Request Bot

[msftclas]

@kiyolee, thanks for signing the contribution license agreement. We will now validate the agreement and then the pull request.

Thanks, Microsoft Pull Request Bot

[ras0219-msft]

Thanks!

We would highly recommend that you use a separate build directory as well.

[kiyolee]

Just figured cmake works differently for these 2 different commands:
(a) cmake {dir}/CMakeLists.txt
(b) cmake {dir}
I accidentally (kind of) used the first form (that ended up not generating cmake files in its own build directory) and so lead to this pull request.