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

runtime/vm/il_printer.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/il_printer.h"
 
 #include "vm/flow_graph_range_analysis.h"
 #include "vm/intermediate_language.h"
 #include "vm/os.h"
 #include "vm/parser.h"
@@ skipping 1061 matching lines @@
     case kTagged:
       return "tagged";
     case kUntagged:
       return "untagged";
     case kUnboxedDouble:
       return "double";
     case kUnboxedInt32:
       return "int32";
     case kUnboxedUint32:
       return "uint32";
-    case kUnboxedMint:
-      return "mint";
+    case kUnboxedInt64:
+      return "int64";
     case kUnboxedFloat32x4:
       return "float32x4";
     case kUnboxedInt32x4:
       return "int32x4";
     case kUnboxedFloat64x2:
       return "float64x2";
     case kPairOfTagged:
       return "tagged-pair";
     case kNoRepresentation:
       return "none";
@@ skipping 195 matching lines @@
   UNREACHABLE();
 }
 
 bool FlowGraphPrinter::ShouldPrint(const Function& function) {
   return false;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart