Support mixed scopes in a single analyzer class

[pavel-mikula-sonarsource]

Since MMF-2297:

• Main-scope rules should run only on Main code
• Test-scope rules should run only on Test code
• All-scope rules should run only on Main code under the Scanner run
• All-scope rules should run on Main and Test code under NuGet or SonarLint use.

This resolution doesn't work correctly when single analyzer class supports diagnostics for Main code and Test code at the same time.