Make it possible to go from Tags back to a Glyph enum.

Remove unused function.

party results in FAR.

Similar to PR #12611. This PR implements metadata roundtripping for
tuples used in generic constraints. Completes the generic parameter
constraint work listed in #12347.

Switch to using TaggedText (from SymbolDisplayPart) for features that want to display classified text.

Decouple the InteractiveWorkspace from needing a InteractiveEvaluator

* Add support for a new ProjectShimFactory to be consumed by CPS.

1. IProjectShim and IProjectShimFactory are the primary interfaces being introduced that CPS will use to forward project system changes to workspace hosts.
2. Refactored the UpdateOptions code in AbstractRoslynProject and sub-types so that it can be shared with the new project shim.

TODO: Add IVT to CPS binaries to enable consuming these APIs (need to follow up with DavKean)

* Add support for a new ProjectShimFactory to be consumed by CPS

1. IProjectShim and IProjectShimFactory are the primary interfaces being introduced that CPS will use to forward project system changes to workspace hosts.

2. Refactored the UpdateOptions code in AbstractRoslynProject and sub-types so that it can be shared with the new project shim.

3. Add IVT to CPS projects to enable consuming these APIs.

* Fix tests

* Add tests for new CPS project shim.

* Fix the tests and update the Shim factory API to take CommandLineArguments.

* Fix VSI test - VB compilation options must also contain latest parse options

* Some more code refactoring to ensure that for the CPS shim we avoid getting properties through the hierarchy while creating the shim and adding new source files.

* Some more code refactoring to address review feedback:

1. Rename IProjectShim and IProjectShimFactory to IProjectContext and IProjectContextFactory respectively.
2. Add a new sub-type of AbstractProject, namely "AbstractLegacyProject", for legacy C# and VB project system shims. All the Hierarchy accesses for computing properties have been moved to this sub-type.
3. Move legacy project system specific interface implementations (IVsHierarchyEvents, IIntellisenseBuildTarget and ICompilerOptionsHostObject) to AbstractLegacyProject.
4. Merge AbstractRoslynProject into AbstractProject - the only addition in AbstractRoslynProject seem to be support for VsENCRebuildableProjectImpl, which was anyways an optional field.

* Change the name of the flag taken by AddSourceFile to "isInCurrentContext"

* Address review feedback

* Fix tests broken by last commit

* Further cleanup of options setting infrastructure

* Minor refactoring of the Options setting APIs

Everything only needed the IInteractiveWindow. This makes life easier
for TypeScript.

Unwind some Linq in a relatively hot path

Debugger locals show wrong value for parameter changed and captured by closure in VB

Revise and simplify the syntax model for out var