[lldb] Check if C++ interop is enabled on CU instead of whole module

Checking if C++ interop is enabled can be extremely slow if the project
is big enough. We have changed this to checking only the compile unit
instead, but one usage of the old API slipped by.

rdar://147009063

Author: augusto2112

lldb/source/Plugins/TypeSystem/Swift/SwiftASTContext.cpp

@@ -2792,7 +2792,7 @@ SwiftASTContext::CreateInstance(const SymbolContext &sc,
     swift_ast_sp->m_module = module_sp.get();
     auto &lang_opts = swift_ast_sp->GetLanguageOptions();
     lang_opts.EnableAccessControl = false;
-    lang_opts.EnableCXXInterop = module_sp->IsSwiftCxxInteropEnabled();
+    lang_opts.EnableCXXInterop = ShouldEnableCXXInterop(cu);
     if (module_sp->IsEmbeddedSwift())
       lang_opts.enableFeature(swift::Feature::Embedded);
   }