Ensure we fire events on the hosts scheduler.

Fix spelling mistake in CIBuild

Update to NuGet 3.3 again

If analyzer assembly referenced by a project is non-existent (e.g. pending nuget restore), hook up analyzer's UpdatedOnDisk to remove/add an analyzer. This ensures that that when the analyzer assembly shows up on the disk, say via nuget restore, we don't issue the analyzer changed on disk diagnostic but attempt to load and execute the analyzer.

Verified that this fixes VSO #164967

That way we can preserve the invariant that workpsace events all fire on
the UI thread in VS.

Return to blocking waits in the workspace.

Fixes https://github.com/dotnet/roslyn/issues/6989
Fixes https://github.com/dotnet/roslyn/issues/6990

Parameter to Restore.cmd to allow to restore different solution

Fix a few outlining unit tests that were not awaiting their results

Support DirectCast and TryCast expressions in VB IMethodXML

If analyzer assembly referenced by a project is non-existent (e.g. pending nuget restore), hook up analyzer's UpdatedOnDisk to remove/add an analyzer. This ensures that that when the analyzer assembly shows up on the disk, say via nuget restore, we don't issue the analyzer changed on disk diagnostic but attempt to load and execute the analyzer.

Verified that this fixes VSO [#164967](https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems#_a=edit&id=164967)

Ensure that suppression state for build diagnostics shows up as active instead of  <blank> , and build diagnostics are not suppressible from error list, i.e. "Suppress" menu does not show up in the error list.

Fixes VSO #164642

Remove reference to non-existent packages.config

Update solution to match what VS wants it to be

Ensure that suppression state for build diagnostics shows up as active instead of <blank>, and build diagnostics are not suppressible from error list, i.e. "Suppress" menu does not show up in the error list.

Fixes VSO [#164642](https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems#_a=edit&id=164642)

Visual Studio keeps wanting to modify the solution,
letting it, and checking that in.

Change unix bootstrap phase to use CoreCLR

Revert "Update to nuget.exe 3.3"

This reverts commit f7e31421.

Clean up and refactor outlining unit tests

Set Experimental flag for our VSIXes

The first phase of Linux / Mac builds is to build the csc / vbc executables used to build the repo.  That initial sttep must use csc / vbc to build our compilers.  Previously this was just using our NuGet distributed compilers under Mono.  Now it uses our compilers running on coreclr.

Ideally this would be the same compilers as our NuGet packages.  That's not quite available today.  Hence this is built off a spefici SHA instead.

Fix build break caused by merge