[debugger] omit exception events for rethrown exceptions in async.

src/interpreter/bytecode-generator.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/code-stubs.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-register-allocator.h"
@@ skipping 2242 matching lines @@
       builder()
           ->MoveRegister(input, value)
           .LoadTrue()
           .StoreAccumulatorInRegister(done)
           .CallRuntime(Runtime::kInlineCreateIterResultObject, value, 2);
       execution_control()->ReturnAccumulator();
     }
 
     builder()->Bind(&resume_with_throw);
     builder()->SetExpressionPosition(expr);
-    builder()->LoadAccumulatorWithRegister(input).Throw();
+    builder()->LoadAccumulatorWithRegister(input);
+    if (expr->rethrow_on_exception()) {
+      builder()->ReThrow();
+    } else {
+      builder()->Throw();
+    }
 
     builder()->Bind(&resume_with_next);
     builder()->LoadAccumulatorWithRegister(input);
   }
   execution_result()->SetResultInAccumulator();
 }
 
 void BytecodeGenerator::VisitThrow(Throw* expr) {
   VisitForAccumulatorValue(expr->exception());
   builder()->SetExpressionPosition(expr);
@@ skipping 893 matching lines @@
   return execution_context()->scope()->language_mode();
 }
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return TypeFeedbackVector::GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8