MSTEST0027: Use Async suffix for async methods suppressor

Suppressor description

Suppress the VSTHRD200: Use Async suffix for async methods diagnostic for test methods.

The Async suffix helps callers recognize APIs that they need to await. MSTest invokes test methods through the test runner, which recognizes their return types and awaits them without relying on their names. Test names can therefore describe the behavior under test without adding an Async suffix solely to satisfy a call-site naming convention.

When to disable suppressor

.NET suppressors cannot be disabled.