Merge dev15.3.x to master

Replace links to Visual Studio 2015 with VS2017

Be more resilient to external errors when trying to create our underlying persistent storage

Fix a null ref in symbol tree info.

Update test.

Always offer to fix an expression-bodied accessor used on an entity where it's not allowed.

Bump the version number to 2.3.1

Ensure we clean up RuleSetFiles when we close the solution

[Test failure] BasicExpressionEvaluator: COMException : Operation not supported. Unknown error: 0x8971003c (#20841)

* "Enable integration tests (#20216)"

This reverts commit 2fba37a6.

* removing unnecessary dispose actions

Perform the initial tagging for a file as fast as possible so that that the file appears 'complete' immediately after opening.

Print out more information in tests when we get an exception.

Disable BasicExpressionEvaluator tests

Add more teams to CODEOWNERS

This reverts commit e33f32f44895c2b7907113557eff0d54d2ea9d55, reversing
changes made to 70097e0c96319d80e1f6faef85b9607cb2311692.

Convert all project files to use globs instead of explicitly listing source files

Add tuple declarations to AllInOneCSharpCode

Update VSSDK package list

[StringTable] Fix bug in Add(string, int, int)

Related to failures in https://github.com/dotnet/roslyn/issues/20711

Increment stream version so we invalidate all existing streams.

Only compute checksums when getting an actual new project instance.

Remove code that could not be hit during parameter parsing.