[interpreter] Implement support for the --trace flag.

src/interpreter/bytecode-array-builder.cc

Index: src/interpreter/bytecode-array-builder.cc
diff --git a/src/interpreter/bytecode-array-builder.cc b/src/interpreter/bytecode-array-builder.cc
index d8698fe9595a62e796d27f6b0dffd59e04ed1e84..4102c65a3881a0c951d7c118292000386f385ba9 100644
--- a/src/interpreter/bytecode-array-builder.cc
+++ b/src/interpreter/bytecode-array-builder.cc
@@ -716,14 +716,6 @@ BytecodeArrayBuilder& BytecodeArrayBuilder::MarkTryEnd(int handler_id) {
   return *this;
 }
 
-void BytecodeArrayBuilder::EnsureReturn() {
-  if (!return_seen_in_block_) {
-    LoadUndefined();
-    Return();
-  }
-  DCHECK(return_seen_in_block_);
-}
-
 BytecodeArrayBuilder& BytecodeArrayBuilder::Call(Register callable,
                                                  RegisterList args,
                                                  int feedback_slot,