roslynator.dotnet.cli throws System.ArgumentException on xunit 2.8.1 projects

[ArwynFr]

Product and Version Used:
'roslynator.dotnet.cli' (version '0.8.8')

Steps to Reproduce:
Full example: ArwynFr/dotnet-integration-testing#42

Actual Behavior:

[ERR] VerifyRoslyn: System.AggregateException: One or more errors occurred. (Argument contains duplicate analyzer instances. (Parameter 'analyzers'))
  [ERR] VerifyRoslyn:  ---> System.ArgumentException: Argument contains duplicate analyzer instances. (Parameter 'analyzers')
  [ERR] VerifyRoslyn:    at Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers.VerifyAnalyzersArgumentForStaticApis(ImmutableArray`1 analyzers, Boolean allowDefaultOrEmpty)
  [ERR] VerifyRoslyn:    at Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers.VerifyArguments(Compilation compilation, ImmutableArray`1 analyzers, CompilationWithAnalyzersOptions analysisOptions)
  [ERR] VerifyRoslyn:    at Microsoft.CodeAnalysis.Diagnostics.CompilationWithAnalyzers..ctor(Compilation compilation, ImmutableArray`1 analyzers, CompilationWithAnalyzersOptions analysisOptions)
  [ERR] VerifyRoslyn:    at Roslynator.Diagnostics.CodeAnalyzer.AnalyzeProjectCoreAsync(Project project, ImmutableArray`1 analyzers, CancellationToken cancellationToken) in /_/src/Workspaces.Core/Diagnostics/CodeAnalyzer.cs:line 165
  [ERR] VerifyRoslyn:    at Roslynator.Diagnostics.CodeAnalyzer.AnalyzeProjectCoreAsync(Project project, CancellationToken cancellationToken) in /_/src/Workspaces.Core/Diagnostics/CodeAnalyzer.cs:line 132
  [ERR] VerifyRoslyn:    at Roslynator.Diagnostics.CodeAnalyzer.AnalyzeSolutionAsync(Solution solution, Func`2 predicate, CancellationToken cancellationToken) in /_/src/Workspaces.Core/Diagnostics/CodeAnalyzer.cs:line 71
  [ERR] VerifyRoslyn:    at Roslynator.CommandLine.AnalyzeCommand.ExecuteAsync(ProjectOrSolution projectOrSolution, CancellationToken cancellationToken) in /_/src/CommandLine/Commands/AnalyzeCommand.cs:line 80
  [ERR] VerifyRoslyn:    at Roslynator.CommandLine.MSBuildWorkspaceCommand`1.ExecuteAsync(String path, MSBuildWorkspace workspace, CancellationToken cancellationToken) in /_/src/CommandLine/Commands/MSBuildWorkspaceCommand.cs:line 164
  [ERR] VerifyRoslyn:    at Roslynator.CommandLine.MSBuildWorkspaceCommand`1.ExecuteAsync(IEnumerable`1 paths, String msbuildPath, IEnumerable`1 properties) in /_/src/CommandLine/Commands/MSBuildWorkspaceCommand.cs:line 89
  [ERR] VerifyRoslyn:    at Roslynator.CommandLine.Program.AnalyzeAsync(AnalyzeCommandLineOptions options) in /_/src/CommandLine/Program.cs:line 343
  [ERR] VerifyRoslyn:    --- End of inner exception stack trace ---
  [ERR] VerifyRoslyn:    at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
  [ERR] VerifyRoslyn:    at Roslynator.CommandLine.Program.<>c.<Main>b__0_3(MSBuildCommandLineOptions options) in /_/src/CommandLine/Program.cs:line 175
  [ERR] VerifyRoslyn:    at CommandLine.ParserResultExtensions.MapResult[T1,T2,TResult](ParserResult`1 result, Func`2 parsedFunc1, Func`2 parsedFunc2, Func`2 notParsedFunc)
  [ERR] VerifyRoslyn:    at Roslynator.CommandLine.Program.Main(String[] args) in /_/src/CommandLine/Program.cs:line 169

Expected Behavior:

Analyzed solution '/home/runner/work/dotnet-integration-testing/dotnet-integration-testing/dotnet-integration-testing.sln' (in 6,1 s)