[release/5.0] [browser][crypto] Remove restraining not supported attr…

…ibute Primitives (dotnet#43441)

Co-authored-by: Kenneth Pouncey <kjpou@pt.lu>

Fix System.Net.Sockets telemetry (dotnet#42726)

Leftover Utf8String defines are causing ILLinker warnings (dotnet#41680)

The CreateRuntimeRootILLinkDescriptorFile task, which generates most of S.P.CoreLib's ILLink.Descriptor file for coreclr, doesn't respect #ifdefs. So even though FEATURE_UTF8STRING is disabled in the release/5.0 branch, it is still generating entries for Char8 and Utf8String. But since these managed types do not exist, the ILLinker is raising warnings.

To fix this, comment the DEFINE_CLASS entries out of the header file.

Fix dotnet#41654

Minimum CMake downgrade for Linux (dotnet#39044) (dotnet#40471)

Co-authored-by: Santiago Fernandez Madero <safern@microsoft.com>
Co-authored-by: Jan Vorlicek <janvorli@microsoft.com>

Co-authored-by: Jeremy Koritzinsky <jekoritz@microsoft.com>
Co-authored-by: Santiago Fernandez Madero <safern@microsoft.com>
Co-authored-by: Jan Vorlicek <janvorli@microsoft.com>

[release/5.0-preview7] Disallow unrestricted polymorphic deserializat…

…ion in DataSet (dotnet#39314)

Fixes CVE-2020-1147
https://portal.msrc.microsoft.com/en-us/security-guidance/advisory/CVE-2020-1147
See also https://go.microsoft.com/fwlink/?linkid=2132227.

SafeProcessHandle.Unix: fix missing DangerousRelease (dotnet#37412) (d…

…otnet#37446)

Because the SafeProcessHandle was not owned, ReleaseHandle was
not called, causing the wrapped SafeWaitHandle to never release
its resources.

Co-authored-by: Tom Deseyn <tom.deseyn@gmail.com>

Loosen property name collision detection involving hidden properties (d…

…otnet#36936) (dotnet#37105)

* Loosen property name collision detection involving hidden properties

* Delay ignored prop cache creation; add more tests

* Clarify comments

[release/5.0-preview4] Revert processing bundles in framework (dotnet…

…#35679)

This commit reverts:
Revert "Single-File: Process bundles in the framework (dotnet#34274)"
This reverts commit 78b303d.

Revert "Single-File Bundler: Add a FileSize test (dotnet#35149)"
This reverts commit 779588a.

*Customer Scenario*

Publishing apps as a self-contained single-file doesn't work as expected.

* Publish needs to generate hostpolicy and hostfxr separate from the single file bundle
* Cross-platform publishing is incorrect

*Problem*

Since Static-apphost is not yet ready, processing bundle content in hostpolicy means that  hostpolicy and hostfxr DLLs need to be separate from the bundle. This causes self-contained single-file apps to not be a "single file" temporarily. 

The change also requires supporting changes from the SDK, to publish hostfxr and hostpolicy as separate files, and to invoke HostModel library with arguments that facilitate cross-platform publishing.

*Solution*

To solve these, problem, this change reverts:

Revert "Single-File: Process bundles in the framework (dotnet#34274)" commit 78b303d.

and a dependent test-only change:

Revert "Single-File Bundler: Add a FileSize test (dotnet#35149)" commit 779588a.

*Risk*

Medium
The change is contained to only host components: apphost, hostpolicy, and hostfxr.
However, the change is big, and needs testing in runtime and SDK repos.

*Testing*

Manually tested the SDK by inserting apphost, hostfxr, hostpolicy, and hostmodel library from this build into the `dotnet/packs` preview-4 SDK from dotnet/sdk#11518 build.

Verified that:
* Singlefile apps can be published and run OK for  { Windows, Linux, Osx } x {netcoreapp3.0, netcoreapp3.1, netcoreapp5.0} 
* Cross-targeting builds of single-file apps build and run OK (ex: built on Windos, run on Mac).

Fix WriteLargeJsonToStreamWithoutFlushing test (dotnet#34914)

.NET 5.0.0-preview.1