Add the new OP_Once opcode.  Use it to clean up and simplify various
one-time initialization sections in the code, including the fix for
ticket [002caede898ae].

FossilOrigin-Name: 7f00552b739fad79517b042a6ed61abe743a917b
diff --git a/src/vdbeblob.c b/src/vdbeblob.c
index a8728e6..ae77a47 100644
--- a/src/vdbeblob.c
+++ b/src/vdbeblob.c
@@ -273,7 +273,7 @@
 
       /* Configure the OP_TableLock instruction */
 #ifdef SQLITE_OMIT_SHARED_CACHE
-      sqlite3VdbeChangeToNoop(v, 2, 1);
+      sqlite3VdbeChangeToNoop(v, 2);
 #else
       sqlite3VdbeChangeP1(v, 2, iDb);
       sqlite3VdbeChangeP2(v, 2, pTab->tnum);
@@ -283,7 +283,7 @@
 
       /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
       ** parameter of the other to pTab->tnum.  */
-      sqlite3VdbeChangeToNoop(v, 4 - flags, 1);
+      sqlite3VdbeChangeToNoop(v, 4 - flags);
       sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
       sqlite3VdbeChangeP3(v, 3 + flags, iDb);