Port fixes for RHEL69 tests to 2.0

[danmoseley]

https://mc.dot.net/#/product/netcore/200/source/official~2Fcorefx~2Frelease~2F2.0.0~2F/type/test~2Ffunctional~2Fcli~2F/build/20170927.01

@tarekgh since you made these fixes would you mind porting so this goes green? Look like trivial disablings, although a few lines need pasting into PlatformDetection, as it's moved around since 2.0 branched.

[tarekgh]

will try to get into this in the first chance.

[krwq]

Globalization and pipes failures and some FileSystem failures are gone. I do not have context for the remaining System.IO failures - also haven't seen them locally:
https://mc.dot.net/#/product/netcore/200/source/official~2Fcorefx~2Frelease~2F2.0.0~2F/type/test~2Ffunctional~2Fcli~2F/build/20171011.01

Assigning to @JeremyKuhne

[karelz]

Given that 2.0 will be out of support in less than 1 month, closing as Won't Fix.