[fullcodegen] Remove deprecated generator implementation.

src/compiler/ast-graph-builder.cc

 // Copyright 2014 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/compiler/ast-graph-builder.h"
 
 #include "src/ast/compile-time-value.h"
 #include "src/ast/scopes.h"
 #include "src/compilation-info.h"
 #include "src/compiler.h"
@@ skipping 2189 matching lines @@
       break;
     }
   }
 
   ast_context()->ProduceValue(expr, value);
 }
 
 
 void AstGraphBuilder::VisitYield(Yield* expr) {
   // Generator functions are supported only by going through Ignition first.
-  SetStackOverflow();
-  ast_context()->ProduceValue(expr, jsgraph()->UndefinedConstant());
+  UNREACHABLE();
 }
 
 
 void AstGraphBuilder::VisitThrow(Throw* expr) {
   VisitForValue(expr->exception());
   Node* exception = environment()->Pop();
   Node* value = BuildThrowError(exception, expr->id());
   ast_context()->ProduceValue(expr, value);
 }
 
@@ skipping 2147 matching lines @@
     TypeHintAnalysis* type_hint_analysis, SourcePositionTable* source_positions,
     int inlining_id)
     : AstGraphBuilder(local_zone, info, jsgraph, invocation_frequency,
                       loop_assignment, type_hint_analysis),
       source_positions_(source_positions),
       start_position_(info->shared_info()->start_position(), inlining_id) {}
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8