Revert "path: resolve normalize drive letter to lower case"

[seishun]

This fixes realpath, but test-fs-realpath still fails due to a different issue. Looking into it.

See #17.

[bnoordhuis]

The commit log should explain why it reverts f6e5740, i.e. why the change in that commit is wrong.

[bnoordhuis]

@piscisaureus Can you take a look?

[seishun]

I'm not sure how much of the backstory is should include. I've added a short rationale for now.

[bnoordhuis]

Thanks, @seishun.

@piscisaureus PTAL. If this was discussed somewhere (which I believe it was), can you add a link?

[rvagg]

@seishun do the tests enforce this behaviour or do we need a new explicit test to lock it in place?

[seishun]

@rvagg the tests are already case-sensitive, I don't think they could do any better.

By the way, the test still fails with this change due to path.join() changing the case of the drive letter (see nodejs/node-v0.x-archive#7031) due to the path.normalize() change mentioned in node-forward/node#20. Should I go ahead and submit a PR fixing that?

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