Invoke CallToRuntime via Thread instead of ObjectPools.

runtime/vm/assembler_arm.cc

Index: runtime/vm/assembler_arm.cc
diff --git a/runtime/vm/assembler_arm.cc b/runtime/vm/assembler_arm.cc
index 4043fc1ebb84501e089c6ff1e15090ff4ea1731f..6f8cf47916d3a3531c6ea9a85d539cff2188f9b3 100644
--- a/runtime/vm/assembler_arm.cc
+++ b/runtime/vm/assembler_arm.cc
@@ -2754,6 +2754,13 @@ void Assembler::BranchLinkPatchable(const Code& target) {
 }
 
 
+void Assembler::BranchLinkToRuntime() {
+  ldr(IP, Address(THR, Thread::call_to_runtime_entry_point_offset()));
+  ldr(CODE_REG, Address(THR, Thread::call_to_runtime_stub_offset()));
+  blx(IP);
+}
+
+
 void Assembler::BranchLinkWithEquivalence(const StubEntry& stub_entry,
                                           const Object& equivalence) {
   const Code& target = Code::Handle(stub_entry.code());