DisposableWaitAsync often completes synchronously

Pass CancellationToken instead of CancellationTokenSource

Avoid captures in SqlConnection.ReadBlob

Update AnalyzerRunner to support IIncrementalAnalyzer testing

* Learn from comparisons to non-constant, non-null values

* Update comment

* Remove unused local function

* Remove another unused local function

* Check for null constant before trying to learn from notNull == maybeNull. Add tests

* More tests, more cleanup

* Add conditional access with || test

* More test updates from feedback

* Cleanup

* Change some locals in tests to parameters

Update FindImplementationsForInterfaceMemberAsync to correctly handle ambiguous type returns (#35853)

FindImplementationsForInterfaceMemberAsync checks for forwarded types using SymbolFinder.OriginalSymbolsMatch, which expects non-null compilation for both the project containing the interface and the project containing the symbol to compare to. Until now, most instances have found equivalence without falling through, but in cases where the type forwarding isn't completely verified a non-null compilation for the interface symbol is needed as well. See VerifyForwardedTypes for the logic being used.

In #35786 the type System.Text.Encoding is provided by a a NuGet reference and could be ambiguous based on the build target. The OOP service attempts to find the correct type resolution but needs the original symbol compilation to verify.

Without this fix, FindAllReferences may cause a null deref and fail.

Fixes #35786

* Update ILAsm and ILDasm version to match expected SDK version

* Fixed version numbers

Add initial support for 'notnull' generic type constraint.

See https://github.com/dotnet/csharplang/blob/master/meetings/2019/LDM-2019-05-15.md
Also fixes #36005.

* Add InteractiveHost as a NuGet package

* Make InteractiveWindow a package dependency

* Update InteractiveWindow version to 2.8.0

* Add missing package dependencies

Add EditorConfig feature flag

Generate assembly version without using the patch version.

Add initial checkpointing to the nullable walker.

Don't capture BoundNode when creating a LazyNoneOperation

Specify the version number in pieces so we can generate the assembly version using just the major and minor version numbers.

Don't read the same property twice in pattern matching when accessed through the same underlying object, but references of different types.
Fixes #34933

* Cleanup style

* Remove BlueSquiggleForBuildDiagnostic

* TableDataSource refactoring

* Remove DiagnosticData.Workspace

* Fix workspace reference

* Simplify GetTrackingPoints

* Simplify deduplication

* EqualsModuloLocation

* Simplify navigate to

* Specialize table item

* Fix assert

* Feedback

* Dedup TryNavigateTo

* Couple of renames

Merge release/dev16.2-preview2 to master

This change produced a 806MB (11.3%) allocation reduction in the scenario
described by #36114.

This change produced a 535MB (7.5%) allocation reduction in the scenario
described by #36114.

Improves the workaround for Microsoft/MSBuildLocator#16

Don't offer 'convert if to conditional' if it crosses a preprocessor directive.

Add Default Interface Implementation tests for VB

Related to #35820, #35821, #35823, #35824, #35827, #35834, #35852, #35885, #35911, #35948.

Port DisposeAnalyzers to release/dev16.2-preview2