Fix the date time set in file by removing the ':'.

This is the same code than the one under SendCore. The date time should
not have the : (time zone offset) to be able to use the file.
[Mono.Parallel] Removed broken Mono.Threading.Tasks code

The code in MonoTaskExtensions.cs relied on the internal method Execute(Action<Task>) in System.Threading.Tasks.Task which was removed in 0a66e60.
Added test that covers bug 18482.
Fixed bug 18482. Reseting all private key values to null is required because a new import may not overwrite existing values.
Added stress test to ConcurrentQueue.TryPeek.
The test checks that in some race condition the queue does not return null.
Changed TryPeek to handle race condition with Dequeue.
Dequeue sets the head.Value to its default. When TryPeek is interrupted in the process of retrieving the value some times Dequeue sets the value to its default. TryPeek now checks the head has not been changed before returning the value.
Test that DeflateStream.Read does read an empty stream. Covers #19313.
Removed DeflateStream.UnmanagedRead Read loop. Fixes #19313.
If the base_stream was a NetworkStream UnmanagedRead loop would call base_stream.Read a second time and block until one byte was available to return. Without the loop UnmanagedRead will only read the base_stream once.
[jit] Avoid licm for volatile variables, ssa ignores them so we can't detect whenever they are loop invariant by looking at phi nodes.
[MS.Build] metadata is also replaced its windows path separators.
[MS.Build] disable failing test.

It somehow passes on my dev. environment so I cannot reproduce...
[msbuild] fix some weird local result variable initialization issue.

I cannot explain why, but this affects building solution that has more than
one projects for MS.Build.dll. <MSBuild/> task returns false for successful
builds without this change.
Most likely codegen or runtime issue, but a bit too high level to drill down.
- ADDED: Support to read out Interface flags on OS X
- ADDED: Implemented NetworkInterface property "OperationalStatus" to be UP, in case the IFF_UP flag is set
- ADDED: Implemented NetworkInterface property "SupportsMulticast" to be true, in case the IFF_MULTICAST flag is set

This change is released under the MIT license.
Merge pull request #1083 from christianhuening/NetworkInterfaceFix

- ADDED: Support to read out Interface flags on OS X
Fixed warning in MSVC by prefixing the macros, MEM_FREE is already defined in winnt.h.
Fixed unsigned/signed mismatch warning.
Fixed unreferenced variables/label warnings in MSVC.
Fixed MSVC warning about different types for formal and actual parameter.
Fixed MSVC warning about unreferenced local variable.
Fixed unreferenced local variable warning in MSVC.