Fix assigned-but-unused (except in an assert) warning with a void cast

clang-tools-extra/clang-tidy/cppcoreguidelines/OwningMemoryCheck.cpp

@@ -192,6 +192,7 @@ void OwningMemoryCheck::check(const MatchFinder::MatchResult &Result) {
   CheckExecuted |= handleReturnValues(Nodes);
   CheckExecuted |= handleOwnerMembers(Nodes);
 
+  (void)CheckExecuted;
   assert(CheckExecuted &&
          "None of the subroutines executed, logic error in matcher!");
 }