[turbofan] Remove dead {is_liveness_analysis_enabled}.

src/compiler/bytecode-graph-builder.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/compiler/bytecode-graph-builder.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/compilation-info.h"
 #include "src/compiler/compiler-source-position-table.h"
@@ skipping 452 matching lines @@
       bytecode_analysis_(nullptr),
       environment_(nullptr),
       osr_ast_id_(osr_ast_id),
       osr_loop_offset_(-1),
       merge_environments_(local_zone),
       exception_handlers_(local_zone),
       current_exception_handler_(0),
       input_buffer_size_(0),
       input_buffer_(nullptr),
       exit_controls_(local_zone),
-      is_liveness_analysis_enabled_(FLAG_analyze_environment_liveness),
       state_values_cache_(jsgraph),
       source_positions_(source_positions),
       start_position_(shared_info->start_position(), inlining_id) {}
 
 Node* BytecodeGraphBuilder::GetNewTarget() {
   if (!new_target_.is_set()) {
     int params = bytecode_array()->parameter_count();
     int index = Linkage::GetJSCallNewTargetParamIndex(params);
     const Operator* op = common()->Parameter(index, "%new.target");
     Node* node = NewNode(op, graph()->start());
@@ skipping 1814 matching lines @@
         it->source_position().ScriptOffset(), start_position_.InliningId()));
     it->Advance();
   } else {
     DCHECK_GT(it->code_offset(), offset);
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8