[Swift-ObjC-Interop] Speculative cyclic lookup fix

The lookup to resolve an ObjC forward declaration
to its potential native Swift definition within
a mixed module is becoming cyclic somehow.

The old uncached lookup still works, so it seems
this is an issue with cache invalidation somehow.
Until the route of the issue, use the old uncached
lookup method.

Author: NuriAmari

lib/ClangImporter/ImportDecl.cpp

@@ -4525,7 +4525,13 @@ namespace {
         SmallVector<Decl *, 4> matchingTopLevelDecls;
 
         // Get decls with a matching @objc attribute
-        module->lookupTopLevelDeclsByObjCName(matchingTopLevelDecls, name);
+        module->getTopLevelDeclsWhereAttributesMatch(
+            matchingTopLevelDecls, [&name](const DeclAttributes attrs) -> bool {
+              if (auto objcAttr = attrs.getAttribute<ObjCAttr>())
+                if (auto objcName = objcAttr->getName())
+                  return objcName->getSimpleName() == name;
+              return false;
+            });
 
         // Filter by decl kind
         for (auto result : matchingTopLevelDecls) {