[vm] Rename *MintOp to *Int64Op to emphasis that they operate on unboxed values.

runtime/vm/flow_graph_type_propagator.cc

Index: runtime/vm/flow_graph_type_propagator.cc
diff --git a/runtime/vm/flow_graph_type_propagator.cc b/runtime/vm/flow_graph_type_propagator.cc
index c86ebb32cd90299aa91d29231dad071371312445..7a2fa75290324bc36ff2c952d9dd5a1e9a014fb0 100644
--- a/runtime/vm/flow_graph_type_propagator.cc
+++ b/runtime/vm/flow_graph_type_propagator.cc
@@ -1120,17 +1120,17 @@ CompileType ConstraintInstr::ComputeType() const {
   return CompileType::FromCid(kSmiCid);
 }
 
-// Note that MintOp may produce Smi-s as result of an
+// Note that Int64Op may produce Smi-s as result of an
 // appended BoxInt64Instr node.
-CompileType BinaryMintOpInstr::ComputeType() const {
+CompileType BinaryInt64OpInstr::ComputeType() const {
   return CompileType::Int();
 }
 
-CompileType ShiftMintOpInstr::ComputeType() const {
+CompileType ShiftInt64OpInstr::ComputeType() const {
   return CompileType::Int();
 }
 
-CompileType UnaryMintOpInstr::ComputeType() const {
+CompileType UnaryInt64OpInstr::ComputeType() const {
   return CompileType::Int();
 }
 
@@ -1330,7 +1330,7 @@ CompileType UnboxInstr::ComputeType() const {
     case kUnboxedInt32x4:
       return CompileType::FromCid(kInt32x4Cid);
 
-    case kUnboxedMint:
+    case kUnboxedInt64:
       return CompileType::Int();
 
     default: