Fix fake/clone tests on Windows

[HebaruSan]

Problem

Running .\build.ps1 test on Windows:

1) Error : Tests.Core.KSPManagerTests.CloneInstance_ToNotEmptyFolder_ThrowsIOException
System.IO.IOException : The process cannot access the file 'shouldntbehere.txt' because it is being used by another process.
   at System.IO.Directory.DeleteHelper(String fullPath, String userPath, Boolean recursive, Boolean throwOnTopLevelDirectoryNotFound, WIN32_FIND_DATA& data)
   at System.IO.Directory.Delete(String fullPath, String userPath, Boolean recursive, Boolean checkHost)
   at Tests.Core.KSPManagerTests.CloneInstance_ToNotEmptyFolder_ThrowsIOException() in C:\Users\Paul\github\CKAN\Tests\Core\KSPManager.cs:line 144

2) Error : Tests.Core.KSPManagerTests.FakeInstance_InNotEmptyFolder_ThrowsBadInstallLocationKraken
System.IO.IOException : The process cannot access the file 'shouldntbehere.txt' because it is being used by another process.
   at System.IO.Directory.DeleteHelper(String fullPath, String userPath, Boolean recursive, Boolean throwOnTopLevelDirectoryNotFound, WIN32_FIND_DATA& data)
   at System.IO.Directory.Delete(String fullPath, String userPath, Boolean recursive, Boolean checkHost)
   at Tests.Core.KSPManagerTests.FakeInstance_InNotEmptyFolder_ThrowsBadInstallLocationKraken() in C:\Users\Paul\github\CKAN\Tests\Core\KSPManager.cs:line 194

3) Error : Tests.Core.KSPManagerTests.FakeInstance_ValidArgumentsWithDLC_ManagerHasValidInstance
System.IO.IOException : The process cannot access the file 'registry.locked' because it is being used by another process.
   at System.IO.Directory.DeleteHelper(String fullPath, String userPath, Boolean recursive, Boolean throwOnTopLevelDirectoryNotFound, WIN32_FIND_DATA& data)
   at System.IO.Directory.Delete(String fullPath, String userPath, Boolean recursive, Boolean checkHost)
   at Tests.Core.KSPManagerTests.FakeInstance_ValidArgumentsWithDLC_ManagerHasValidInstance() in C:\Users\Paul\github\CKAN\Tests\Core\KSPManager.cs:line 214

Causes

CKAN/quotes.txt

Lines 11 to 16 in df8fb70

	techman83: Hehe. :) The Linux style of locking is "here's a tiny
	easy-to-miss note I'm putting on my sandwich, don't eat it!".
	Windows is "I'm locking my sandwich in this safe. Why are you
	worried it will go stale?"
	-- pjf, IRC

Errors 1 and 2: System.IO.File.Create returns an open file handle, which on Windows includes a lock. Deleting the locked file's parent folder isn't allowed.

Error 3: KSP loads its registry.json file and creates a registry.locked file to lock it. On Windows the registry.locked file is itself locked. Deleting this locked file's parent folder also isn't allowed.

Changes

Errors 1 and 2: Now we close the file handle returned by System.IO.File.Create, which releases the lock and allows the folder to be deleted.

Error 3: Now we call RegistryManager.ReleaseLock for the KSP instance, which allows the folder to be deleted.

CloneInstance_ToNotEmptyFolder_ThrowsIOException is also renamed to CloneInstance_ToNotEmptyFolder_ThrowsPathErrorKraken to reflect the exception that is expected.

Fixes #2752.

[DasSkelett]

Nice, thanks for fixing this.
Didn't really feel like looking into Windows file handles and stuff 😅