[gold] Enable MCTargetOptions::AsmVerbose along with emit-asm (#71606)

Print comments into assembly output if we're using `emit-asm`.

Author: mshockwave

llvm/test/tools/gold/X86/emit-asm.ll

@@ -23,3 +23,6 @@ define void @f1() {
 define void @f2() {
   ret void
 }
+
+; Check if comments are emitted into assembly.
+; CHECK: -- End function

llvm/tools/gold/gold-plugin.cpp

@@ -925,6 +925,7 @@ static std::unique_ptr<LTO> createLTO(IndexWriteCallback OnIndexWrite,
     break;
   case options::OT_ASM_ONLY:
     Conf.CGFileType = CodeGenFileType::AssemblyFile;
+    Conf.Options.MCOptions.AsmVerbose = true;
     break;
   }