Fixes VSO Watson [#763828](https://devdiv.visualstudio.com/DevDiv/_workitems/edit/763828)
All the dumps for the watson show that cancellation was requested during analysis, leading to one thread clearing state while other thread faulted.

Merge dev16.0-preview3 to master

Fix assertion in UsePatternMatching analyzer

Fix rootnamespce property name we received from project-system

fix some out-of-sync file names

update mono-devel in dockerfile, and don't cache later commands

* Classify C# 8 ControlKeywords

* Add unit test for C#8 control keyword classification

Fix Formatting Warnings on Build

Include file counts in success message for dotnet-format

Co-Authored-By: Ngenlu <genlu@users.noreply.github.com>

Handle ICoalesceAssignmentOperation in GetValueUsageInfo(operation) h…

Bail out on delegate creation wrapped a in tuple operation

Revert "Delete VisualStudioMetadataReference, which was now an empty type"

This reverts commit 73f1152e. Right now
F# is still implicitly mentioning this type. This has been fixed in
https://github.com/Microsoft/visualfsharp/pull/6153 but until we can
get that rolled out we'll roll back the name change.

Another case where we need PointsTo analysis for precise flow analysis, we bail out as we currently do not perform any PointsTo analysis.

Fixes #32903

Assert when emitting a box IL opcode for ref like type

Fixes #32842

Handle string concat with no string literals in ConvertToInterpolatedString

Avoid touching files that didn't actually change

Complete a number of nullable test issues

Localize regex tests

Fix formatting of positional patterns

dotnet-format --dry-run

Simulate the C# 7 compiler's behavior on traditional switch statements with old language versions (#32818)

Fixes #32806
This was a "forward compatibility" bug, where new compilers would accept code in old language versions that the older compilers would not have accepted.

Bail out on reporting unused parameter diagnostic for special paramet…

Update usages of the source file name when copying a banner to a new file.

Update System.Commandline in dotnet-format