Eliminate dependencies on assemblers and code stubs in precompiled runtime.

runtime/vm/constant_propagator.cc

Index: runtime/vm/constant_propagator.cc
diff --git a/runtime/vm/constant_propagator.cc b/runtime/vm/constant_propagator.cc
index ae046315b50990e603fb3824542babff3a64b91c..9fe62e6a654b11acbe02fd4bebdbaab12422335f 100644
--- a/runtime/vm/constant_propagator.cc
+++ b/runtime/vm/constant_propagator.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/constant_propagator.h"
 
 #include "vm/bit_vector.h"
@@ -1741,3 +1743,5 @@ void ConstantPropagator::Transform() {
 }
 
 }  // namespace dart
+
+#endif  // !defined(DART_PRECOMPILED_RUNTIME)