[Exclusivity] Allow testing the -Onone pipeline with access markers.

Markers are always eliminated before -O passes.

At -Onone, markers can be enabled via command line for all -Onone passes.

lib/FrontendTool/FrontendTool.cpp

@@ -671,6 +671,9 @@ static bool performCompile(std::unique_ptr<CompilerInstance> &Instance,
     SharedTimer timer("SIL optimization");
     if (Invocation.getSILOptions().Optimization >
         SILOptions::SILOptMode::None) {
+
+      runSILOptPreparePasses(*SM);
+
       StringRef CustomPipelinePath =
         Invocation.getSILOptions().ExternalPassPipelineFilename;
       if (!CustomPipelinePath.empty()) {