Move dx.dex.code.DalvOps -> dx.io.Opcodes.

This breaks a nascent circular dependency, keeping dx.io the lower layer.

Bonus: While I was in the territory, I clarified the data payload
opcodes, including adding explicit constants for them.

Change-Id: I8655064ebc3b5713cbb4a6c83bcc90984393701f
diff --git a/opcode-gen/opcode-gen.awk b/opcode-gen/opcode-gen.awk
index 86e7cae..e269abf 100644
--- a/opcode-gen/opcode-gen.awk
+++ b/opcode-gen/opcode-gen.awk
@@ -80,7 +80,7 @@
     for (i = 0; i <= MAX_OPCODE; i++) {
         if (isUnused(i) || isOptimized(i)) continue;
         if (isFirst[i] == "true") {
-            printf("    //     DalvOps.%s\n", constName[i]);
+            printf("    //     Opcodes.%s\n", constName[i]);
         }
     }
 }
@@ -95,8 +95,8 @@
         nextOp = (nextOp == -1) ? "NO_NEXT" : constName[nextOp];
 
         printf("    public static final Dop %s =\n" \
-               "        new Dop(DalvOps.%s, DalvOps.%s,\n" \
-               "            DalvOps.%s, Form%s.THE_ONE, %s,\n" \
+               "        new Dop(Opcodes.%s, Opcodes.%s,\n" \
+               "            Opcodes.%s, Form%s.THE_ONE, %s,\n" \
                "            \"%s\");\n\n",
                constName[i], constName[i], family[i], nextOp, format[i],
                hasResult[i], name[i]);
@@ -119,7 +119,7 @@
         }
 
         printf("    public static final Info %s =\n" \
-               "        new Info(DalvOps.%s,\n" \
+               "        new Info(Opcodes.%s,\n" \
                "            InstructionCodec.FORMAT_%s, %s);\n\n", \
                 constName[i], constName[i], toupper(format[i]), itype);
     }