[C++20][Modules] Correct an assert for modules-ts.

When adding the support for modules partitions we added an assert that the
actual status of Global Module Fragments matches the state machine that is
driven by the module; keyword.

That does not apply to the modules-ts case, where there is an implicit GMF.

Differential Revision: https://reviews.llvm.org/D122394

clang/lib/Sema/SemaModule.cpp

@@ -206,7 +206,7 @@ Sema::ActOnModuleDecl(SourceLocation StartLoc, SourceLocation ModuleLoc,
       ModuleScopes.back().Module->Kind == Module::GlobalModuleFragment)
     GlobalModuleFragment = ModuleScopes.back().Module;
 
-  assert((!getLangOpts().CPlusPlusModules ||
+  assert((!getLangOpts().CPlusPlusModules || getLangOpts().ModulesTS ||
           SeenGMF == (bool)GlobalModuleFragment) &&
          "mismatched global module state");