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.
[mcs] Keep stack populated when array initializer contains await
[mcs] Emit correct value type collection initialization when second initializer uses await
[corlib] Set AggregateException message text in all overloads
[mcs] Always store hidden catch variable when clause contains await
Added fix for Bug 11630
[runtime] Rewrite MemoryMappedFile to support named mappings.
[runtime] Fix share/private flags when doing file mmap.
[System.Core] Add new tests for MemoryMappedFile.
Monodoc: Fix for CDATA bug (https://bugzilla.xamarin.com/show_bug.cgi?id=17850). Reverts 3f361e1a263fc23680beab62eadde0cd3e4ac64d

Removed code that stripped CDATA statements (but not blocks) from input when showing a namespace page:

The function Ecma2Html.WrapStream(TextReader,Dictionary<String,String>) very explicitly returns a new `AvoidCDataTextReader` when the system is showing a namespace. The `AvoidCDataTextReader` strips the CDATA statement, but not it's internal contents. The intent, according to AvoidCDataTextReaderTests, is to allow class summaries of this form:

"<elements><summary>Addressbook APIs.</summary><remarks /><class name=""ABAddressBook"" fullname=""MonoTouch.AddressBook.ABAddressBook"" assembly=""monotouch""><summary><![CDATA[
      Provides access to the system Address Book.]]>
    </summary></class></elements>"

But that form is not desired.

The bug arose because the input to `WrapStream` is very large (it actually includes the entire *description* for each class and member in the namespace!). If any CDATA-block contained entities such as, e.g., < or >, the resulting XML would (obviously) be ill-formed:

"<xml>This should be valid <![CDATA[<T>]]> </xml>"

would throw because the <T> would be attempted to be parsed as XML. Obviously, samples that contain generics or lambda or XAML would cause this problem.

Although an XMLException was thrown, Macdoc swallows the exception in DocTools.GetHTML(). That is why this caused a silent failure on macdoc and was visible on Webdoc.
[x86] Fix initialization of stackalloc-ed memory in no pushes mode.
[arm] Add an enum for gsharedvt argument marshalling conventions.
[x86] Align stackalloc-ed memory in no pushes mode.