Delete `NonSeekableStream` used in Zip64 tests in favor
of `ForwardOnlyStream` used in Mocks.
Additionally, delete the `ForwardOnlyStream.ReadByte` implementation
as the implementation on the base Stream is sufficient.
Tests fail in Visual Studio because they try to reuse the same scratch
working space, and each test is responsible for resetting the space. To
simplify the test code:
1. Make `TestBase` `IDisposable` and have it create the scratch space
2. Remove `ResetScratch()` as it is now handled by the base class
3. Add a unique ID to each scrach space folder to prevent collisions
* Zip64 introduced seekable behavior into ZipWriter. The position may not be zero.
* Remove some dead code
* Update formats for zip64
* Make version created by and version needed to extract the same
* Running tests is faster than skipping
