Eliminate dependencies on assemblers and code stubs in precompiled runtime.

runtime/vm/runtime_entry_arm64.cc

Index: runtime/vm/runtime_entry_arm64.cc
diff --git a/runtime/vm/runtime_entry_arm64.cc b/runtime/vm/runtime_entry_arm64.cc
index 2186fc36d6edc8128f158e0297140eead063d76e..7564ee8e3f785ca8e77d093d282cdf68a838a991 100644
--- a/runtime/vm/runtime_entry_arm64.cc
+++ b/runtime/vm/runtime_entry_arm64.cc
@@ -38,6 +38,7 @@ uword RuntimeEntry::GetEntryPoint() const {
 }
 
 
+#if !defined(DART_PRECOMPILED_RUNTIME)
 // Generate code to call into the stub which will call the runtime
 // function. Input for the stub is as follows:
 //   SP : points to the arguments and return value array.
@@ -73,6 +74,7 @@ void RuntimeEntry::Call(Assembler* assembler, intptr_t argument_count) const {
     __ BranchLinkToRuntime();
   }
 }
+#endif  // !defined(DART_PRECOMPILED_RUNTIME)
 
 }  // namespace dart