Reapply "Eliminate dependencies on assemblers and code stubs in precompiled runtime."

runtime/vm/branch_optimizer.cc

Index: runtime/vm/branch_optimizer.cc
diff --git a/runtime/vm/branch_optimizer.cc b/runtime/vm/branch_optimizer.cc
index 3693eda40191dfeae53141cd63b17a070defea2c..b6391d07ccdba965301165cdc6f4353e953da750 100644
--- a/runtime/vm/branch_optimizer.cc
+++ b/runtime/vm/branch_optimizer.cc
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+#if !defined(DART_PRECOMPILED_RUNTIME)
+
 #include "vm/branch_optimizer.h"
 
 #include "vm/flow_graph.h"
@@ -340,3 +342,5 @@ void IfConverter::Simplify(FlowGraph* flow_graph) {
 }
 
 }  // namespace dart
+
+#endif  // !defined(DART_PRECOMPILED_RUNTIME)