[turbofan] Improve message for unexpected opcode in simplified lowering.

src/compiler/simplified-lowering.cc

Index: src/compiler/simplified-lowering.cc
diff --git a/src/compiler/simplified-lowering.cc b/src/compiler/simplified-lowering.cc
index 463bf030cd77b920840abfcde5107e0178e6d8b8..fb660c6301f1e81ae9de3f6ff5b3da9d9e8d0f21 100644
--- a/src/compiler/simplified-lowering.cc
+++ b/src/compiler/simplified-lowering.cc
@@ -2460,9 +2460,10 @@ class RepresentationSelector {
         return SetOutput(node, MachineRepresentation::kTagged);
 
       default:
-        V8_Fatal(__FILE__, __LINE__,
-                 "Representation inference: unsupported opcode %s\n.",
-                 node->op()->mnemonic());
+        V8_Fatal(
+            __FILE__, __LINE__,
+            "Representation inference: unsupported opcode %i (%s), node #%i\n.",
+            node->opcode(), node->op()->mnemonic(), node->id());
         break;
     }
     UNREACHABLE();