Explicitly state that suppression state column in error list is only supported for intellisense diagnostics (#13387)

1. Suppression state column shows N/A for build diagnostics.
2. A descriptive tooltip is now shown on error list entries with unsupported suppression state, guiding users to switch to intellisense diagnostics for suppression.

Fixes #11371

Implement code fix for CS1573

Adding a secondary check to validate whether we are on Dev15 Preview 4 or Dev15 Preview 3 from within VS.

Use Tuple syntax in EE for Type and Value

Remove redundant GetDeclaredSymbol(DeclarationExpressionSyntax declarationSyntax, ...) API.

Adding a secondary check to validate whether we are on Dev15 Preview 4 or Dev15 Preview 3 from within VS.

[Codestyle]: Prefer predefined type or framework type

* generate binary literals for enums that are already binary

* adds test for binary enum int-max

Speed up SymbolFinder by store inheritance information in our metadata index.

This is a collective PR for local functions that represents all the work around the design changes allowing local functions to be referenced from anywhere in scope. The first commit implements the necessary changes to lowering and the second implements the changes to definite assignment.

Both changes have already been reviewed.

Fix leak of projects in VisualStudioProjectTracker.WorkspaceHostState

This PR implements the design changes for flow analysis in local
functions, specifically the decision to allow local functions to be
declared anywhere in the method and only have captured usages considered
at the local function use site, rather than the declaration site.

The key points of the algorithm are as follows:

    1. Visit local functions recursively:
        a. For each new read/write of a captured variable in the local
           function, record it. If the local function has already been used,
           mark the `stateChangedAfterUse` to `true`, indicating that we
           need to visit another pass.
        b. When a local function is used, play back the recorded
           read/writes if the variable is not still captured. Mark the local
           function as used.
    2. Process remaining statements in the parent method, performing
        (1.b) when necessary.
    3. If `stateAfterChanged` has been set to true, visit the entire method
       again (and go to 1).

Fixes #10391.

Fixes #10358.

We had a few different patterns in our codebase. This unifies all of
them to a single helper. We had not one but two (!) different pieces
of code also trying to create dumps if the assertion failed. I've chosen
to toss both of those, since I believe one of two things to be true:

1. The underlying bugs have been fixed, and it's probable the dumping
   code no longer works.
2. The underlying bugs havent been fixed, but we're clearly not hitting
   that fail code.

Run data flow analysis over field initializers when instrumenting for dynamic analysis

This PR addresses changes to local functions described in #10391.
Specifically, it has been decided that it should be legal to reference
local functions defined lexically after the point of reference, i.e.
call a local function defined at the end of a method:

```
    public void Main()
    {
        Local();
        void Local() {}
    }
```

This PR completes the lowering work necessary to correctly emit this
code, although it doesn't modify definite assignment to handle the new
cases created by this change. That work will be completed in a
subsequent PR.

Adjust scope of locals declared within a Deconstruction Declaration Statement according to the latest design.

Improve parser error recovery for deconstruction declarations

Don't allocate a lambda each time we get a hashcode for a named type

Discard a reference to project being emitted when debugging session terminates

Adjust scope of locals declared within a Deconstruction Declaration Statement according to the latest design.

Related to #12597.

Remove dependency on SemanticModel from FindRefs.

Fixes #13291.

* Replace Windows style directory separator char with portable shim directory separator char in include file paths.

Fixes #11978

* Address PR feedback from tmat and attempt to replace the Windows stype separator char only if resolve fails with the original include path.

* Further cleanup/refactoring

Specify how the compiler identifies the core library.