Use cheaper, equivalent predicate. (NFC)

Author: adrian-prantl

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp

@@ -906,7 +906,7 @@ TypeSP DWARFASTParserClang::ParseTypeFromDWARF(const SymbolContext &sc,
           if (class_type) {
             bool alternate_defn = false;
             if (class_type->GetID() != decl_ctx_die.GetID() ||
-                GetContainingClangModuleDIE(decl_ctx_die)) {
+                IsClangModuleFwdDecl(decl_ctx_die)) {
               alternate_defn = true;
 
               // We uniqued the parent class of this function to another