Cleanup: Make CheckClassId instruction more general so it

runtime/vm/flow_graph_compiler_arm.cc

Index: runtime/vm/flow_graph_compiler_arm.cc
diff --git a/runtime/vm/flow_graph_compiler_arm.cc b/runtime/vm/flow_graph_compiler_arm.cc
index b1238061532e708f9cdf546a5f19814437109c32..fdf3257f57a6db6bc91cb598785d9f82ad546fe3 100644
--- a/runtime/vm/flow_graph_compiler_arm.cc
+++ b/runtime/vm/flow_graph_compiler_arm.cc
@@ -1523,13 +1523,13 @@ int FlowGraphCompiler::EmitTestAndCallCheckCid(Label* next_label,
                                                int bias) {
   intptr_t cid_start = range.cid_start;
   intptr_t cid_end = range.cid_end;
-  if (cid_start == cid_end) {
+  if (range.IsSingleCid()) {
     __ CompareImmediate(R2, cid_start - bias);
     __ b(next_label, NE);
   } else {
     __ AddImmediate(R2, R2, bias - cid_start);
     bias = cid_start;
-    __ CompareImmediate(R2, cid_end - cid_start);
+    __ CompareImmediate(R2, range.Extent());
     __ b(next_label, HI);  // Unsigned higher.
   }
   return bias;