[cleanup] Fix signature of RawMachineAssembler::Comment()

Bug: v8:8834
Change-Id: I4d57b15f2d5058511a2c474897a52cac236a6a00
Reviewed-on: https://chromium-review.googlesource.com/c/1488767Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59867}

src/compiler/raw-machine-assembler.cc

@@ -564,7 +564,7 @@ void RawMachineAssembler::Unreachable() {
   current_block_ = nullptr;
 }
 
-void RawMachineAssembler::Comment(std::string msg) {
+void RawMachineAssembler::Comment(const std::string& msg) {
   size_t length = msg.length() + 1;
   char* zone_buffer = zone()->NewArray<char>(length);
   MemCopy(zone_buffer, msg.c_str(), length);

src/compiler/raw-machine-assembler.h

@@ -941,7 +941,7 @@ class V8_EXPORT_PRIVATE RawMachineAssembler {
   void DebugAbort(Node* message);
   void DebugBreak();
   void Unreachable();
-  void Comment(std::string msg);
+  void Comment(const std::string& msg);
 
 #if DEBUG
   void Bind(RawMachineLabel* label, AssemblerDebugInfo info);