Add SpecializedTasks.EmptyTask back

Add few IOperation unit tests for foreach statement

This is being consumed via InternalsVisibleTo, so we can't delete it for
now.

Enable VB IOperation tests on CoreClr

Remove code filtering out operation none children from BoundBlock

* fixed CA1044 in ConsoleIO

* updated override in TestConsoleIO

Merge identical branches in rewrite of Nullable Binary Conditional Operator for CFG

* Fixed error messages around fixed fields (#27424)

* Fixed 26688

* Fixed 26743

* Document breaking change.

* Fix build break

* PR Comments

* Fix breaking change

* Rename confusing API

* Added comment

* Typo in comment

Enable VB semantic tests on CoreClr

Remove SpecializedTasks.EmptyTask

Added null-coalescing-assignment to the C# 8 feature status.

Updating RoslynNugetMoniker to beta8

The CLI toolchain only supports string literals inside of a RESX file.
Other blobs, such as a reference to a file on disk, are not supported.
Instead their value gets embedded directly as a string literal (type is
ignored). Only supported mechanism is to embed them as a manifest
resource stream.

https://github.com/Microsoft/msbuild/issues/2221

Enable VB emit tests on CoreClr

Fixes #22030

* Update branches for target-typed-new and caller-expression

* Add "pattern-based using"

Bind goto case expression even in presence of errors

Assert that IArrayInitializationOperation.Type is always null in test visitors

* Change goldbar text for updating keyboard bindings

* Fix text placeholder

* Update text

Fixes #8891

* Move VS specific targets to VisualStudio.targets

* Move optimization targets to RepoToolset/OptimizationData.targets

* Move SourceLink targets to RepositoryInfo.targets

* Remove workarounds for fixed issues

* Move workrounds to Workarounds.targets

* Clean up binding redirect generation properties

* Remove unused targets

* Normalize PushToBlobFeed parameters to values used by RepoToolset.

Add ControlFlowGraph.Create overload that takes syntax and semantic m…

Infrastructure misc changes

Fixes #21776

The CLI toolchain only supports string literals inside of a RESX file.
Other blobs, such as a reference to a file on disk, are not supported.
Instead their value gets embedded directly as a string literal (type is
ignored). Only supported mechanism is to embed them as a manifest
resource stream.

https://github.com/Microsoft/msbuild/issues/2221