Merge ide-dataflow-analyzer feature branch into master

Move VS MSBuild location to Arcade tools script

Disallow null coalescing assignment in expression trees.

Fix IBC data application

Dataflow analysis based analyzer/fixer to identify unused expression values and parameters

Treat conversions whose operands have no side effects to be operations with no side effects, that can be removed.

Fix an assert introduced my previous commit for conservative analysis in presence of delegate type arguments, where parameter default value is used instead of an explicit delegate argument. This was causing the fast pass (operation tree based symbol usage analysis) to bail out, while the slow pass (control flow graph based symbol usage analysis) to correctly identify and flag unused values.

Conservatively handle delegates passed as arguments to method invocations by reseting state so all the current writes are assumed to be read.
Also ensure that we report unused parameters when we bail out from flow analysis, as the latter should only prevent us from reporting unused values.

Add an API to pass additional msbuild properties to workspace

1. Do not invoke SyntaxEditorBasedCodeFixProvider.FixAllAsync if there are no diagnostics to fixed.
2. Handle flow captures that are both lvalue and rvalue captures (left of a compound assignment operation where right has conditional code).

* fixed a race where solution cralwer used wrong solution for it to process.

race is this.

1. solution crawler picked up a solution
2. before processing the solution, workitem got changed
3. and then picked up an work item from the queue
4. and use the work item with the solution that got picked up in step 1

step 2 is happening beacuse solution has changed, but step 4 used old solution from step 1
that doesn't have effects of the solution changes.

solution crawler must pick up solution after it has picked up work item from the queue so that new changes of a solution get enqueued as new work item,

* Update src/Features/Core/Portable/SolutionCrawler/WorkCoordinator.NormalPriorityProcessor.cs

thank you
Co-Authored-By: Nheejaechang <hechang@microsoft.com>

* addressing feedback

Create TempPE compiler for the new project system

Delete unused packages

Typos

Fix up the implementation of IDocumentTrackingService

Fix goto-def and glyph for builtin operators.

We get these from them now, we don't make them ourselves.

This is still needed for running unit tests, but just in one place. We
can remove it everywhere else.