Directory move fix (dotnet/corefx#40570)
* Fix to support case-insensitive directory moving/renaming
* More tests for other directories
* Include throwing win32 exp upon directory already existing
* Added ) that I dropped in previous rebase
* Directory get with pattern to check for case sensitivity
* Error message fix
* Rework to support multiple edge cases
* Rework to only support moving to the same directory case insentivity
* Handle situations for case-sensitive file systems
* Test changes
* Stopped modifying environment's current directory
* Cleanup, and tests for drive differences
* Only set route to lower, but only only compare roots ordinally
* Add additional if to check if any directory with that name exists
* Edit to what path to use
* Use destination path.
* Rework file directory scan
* Make utility function due to Any() with empty returning true
* Get the full path before getting the filename
* Check if the directory name is null or empty
* Removed extra line
* Now Defering to the OS for if the directory already exists
* Remove extra semi-colon
* Test Edit
* Comment edit
* Actually test the functionality the test is built for
* Remove platform specific tests and make them platform agnostic
* Target only OSX
* Target all platforms other than linux itself
* Changed how we detect case variants
* Remove unix specific test
* Convert OSX test into no-op test
* Code review feedback and additional tests
* Case-Sensitive file systems specific tests
* Fix to not include osx with other unixes
* Removed a ,
Commit migrated from https://github.com/dotnet/corefx/commit/
e9ce2f734698ab5bf13f947c281fa4bec67b0216