Eliminate dependencies on assemblers and code stubs in precompiled runtime.

runtime/vm/weak_code.cc

Index: runtime/vm/weak_code.cc
diff --git a/runtime/vm/weak_code.cc b/runtime/vm/weak_code.cc
index 7f2f4064ff37f551baba76af68badef9dae5b39a..a13c9ab1c9ba4cf8cdc569fe11348b0a2a44de60 100644
--- a/runtime/vm/weak_code.cc
+++ b/runtime/vm/weak_code.cc
@@ -63,10 +63,14 @@ bool WeakCodeReferences::IsOptimizedCode(const Array& dependent_code,
 void WeakCodeReferences::DisableCode() {
   Thread* thread = Thread::Current();
   const Array& code_objects = Array::Handle(thread->zone(), array_.raw());
+#if defined(DART_PRECOMPILED_RUNTIME)
+  ASSERT(code_objects.IsNull());
+  return;
+#else
   if (code_objects.IsNull()) {
     return;
   }
-  ASSERT(!FLAG_precompiled_runtime);
+
   UpdateArrayTo(Object::null_array());
   // Disable all code on stack.
   Code& code = Code::Handle();
@@ -132,6 +136,7 @@ void WeakCodeReferences::DisableCode() {
       }
     }
   }
+#endif  // defined(DART_PRECOMPILED_RUNTIME)
 }
 
 }  // namespace dart