VM+RISC: Share object pool entries for allocation stubs.

runtime/vm/intermediate_language_arm64.cc

Index: runtime/vm/intermediate_language_arm64.cc
diff --git a/runtime/vm/intermediate_language_arm64.cc b/runtime/vm/intermediate_language_arm64.cc
index 12b9f3db8b369a2931071cf86bbcb14087a3d2cd..1eabe23055f10867cae5ef623d5ba392d905b47c 100644
--- a/runtime/vm/intermediate_language_arm64.cc
+++ b/runtime/vm/intermediate_language_arm64.cc
@@ -5751,8 +5751,9 @@ void AllocateObjectInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 
 void DebugStepCheckInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   ASSERT(!compiler->is_optimizing());
-  compiler->GenerateCall(
-      token_pos(), *StubCode::DebugStepCheck_entry(), stub_kind_, locs());
+  __ BranchLinkPatchable(*StubCode::DebugStepCheck_entry());
+  compiler->AddCurrentDescriptor(stub_kind_, Thread::kNoDeoptId, token_pos());
+  compiler->RecordSafepoint(locs());
 }