[mlir][target] RAII wrap moduleToObject timer to ensure call clear function

Author: MikaOvO

mlir/lib/Target/LLVM/NVVM/Target.cpp

@@ -673,6 +673,7 @@ NVPTXSerializer::moduleToObject(llvm::Module &llvmModule) {
   llvm::Timer moduleToObjectTimer(
       "moduleToObjectTimer",
       "Timer for perf llvm-ir -> isa and isa -> binary.");
+  auto clear = llvm::make_scope_exit([&]() { moduleToObjectTimer.clear(); });
   // Return LLVM IR if the compilation target is `offload`.
 #define DEBUG_TYPE "serialize-to-llvm"
   LLVM_DEBUG({