Merge RawICData::range_feedback_ field into RawICData::state_bits_.

runtime/vm/assembler_x64.cc

Index: runtime/vm/assembler_x64.cc
diff --git a/runtime/vm/assembler_x64.cc b/runtime/vm/assembler_x64.cc
index c9a3fd44e2aae1a830c40af56f4f165fa762f4e1..c14b1832b4ea2abbc2b619d2963aa8cbd8ae3feb 100644
--- a/runtime/vm/assembler_x64.cc
+++ b/runtime/vm/assembler_x64.cc
@@ -3825,10 +3825,8 @@ void Assembler::UpdateRangeFeedback(Register value,
                                     Label* miss) {
   ASSERT(ICData::IsValidRangeFeedbackIndex(index));
   ComputeRange(scratch, value, miss);
-  if (index != 0) {
-    shll(scratch, Immediate(ICData::kBitsPerRangeFeedback * index));
-  }
-  orl(FieldAddress(ic_data, ICData::range_feedback_offset()), scratch);
+  shll(scratch, Immediate(ICData::RangeFeedbackShift(index)));
+  orl(FieldAddress(ic_data, ICData::state_bits_offset()), scratch);
 }