Another clarifying rename and a bit more automation.

kNumDalvikInstructions is now kNumPackedOpcodes, there is a new
kMaxOpcodeValue, and both are generated by opcode-gen.

Change-Id: Ic46f1f52d2d21382452c8e777024f4a985ad31d3
Bonus: Reworded the switch and array data comment for clarity.
diff --git a/vm/compiler/Dataflow.c b/vm/compiler/Dataflow.c
index 924ba62..82f52b9 100644
--- a/vm/compiler/Dataflow.c
+++ b/vm/compiler/Dataflow.c
@@ -21,7 +21,7 @@
 
 /*
  * Main table containing data flow attributes for each bytecode. The
- * first kNumDalvikInstructions entries are for Dalvik bytecode
+ * first kNumPackedOpcodes entries are for Dalvik bytecode
  * instructions, where extended opcode at the MIR level are appended
  * afterwards.
  *