Update integration test framework

Don't bundle binaries in VisualStudioSetup.Next

Also, don't install it as part of build on Dev14.

Fixes unintended move of banner text, as reported in issue #8797.

Also mentioned converting to string using ToString

* Fix formatting of ref/out parameters in Scripting

This is used when displaying exceptions in csi.

Previously, ref/out parameters in stacktraces were shown incorrectly,
and even threw NRE when the type of the ref/out parameter was a type parameter.

Fixes the fixable part of #11284

Do a better job inferring where type parameters will be used when generating methods.

Fixes #11141

Order Fully-Qualify results if we believe a certain fix would be better than another one

Fixes #11071

Removed stray > from documentation comments

This supports running an analyzer that warns when a user implements these interfaces.

A prerequisite to fix https://github.com/dotnet/roslyn-analyzers/issues/863.

- Copied the remark from `ISymbol` derivations on all public interfaces that derive from `IOperation`
- Added remark and `[InternalImplementationOnly]` on `IOperation`
- Removed `[InternalImplementationOnly]` from `ISourceAssemblySymbol` because it was only there, unneeded

Allow to open existing projects (if solution already contains that
project).

Support VS "15" specific features

More cleanup to do between RoslynCompletionSet and
FilteredRoslynCompletionSet.

1. Reference a bunch of stuff from Nuget packages instead of VS.
2. Move to Update 2 versions of packages.
3. Now that we are using the packages, we're referencing
   Microsoft.VisualStudio.Shell.14.dll instead of .15 again.  This means
   that types that moved to Shell.Immutable.15 are not type forwarders.
   Luckily we didn't need anything from Shell.Immutable.15 in the project
   where it was a problem.

Add missed code hooking up the option for /**/ comments

Extending the supported functionality of the VisualStudio IntegrationTest Utilities and adding the start of 'CSharpAutomaticBraceCompletion'

Avoid loading the Elfie dll until the user actualy enables the search feature.

Wrapping all `DTE` calls in `IntegrationHelper.RetryRpcCall`, as they tend to fail with `RPC_E_CALL_REJECTED`.

Improve OrderPreservingMultiDictionary.

Fixed complex trivia tab indentation