A new implementation of sqlite3VdbeMakeLabel() is faster and makes fewer

memory allocations by deferring memory allocation until 
sqlite3VdbeResolveLabel() is called, at which point the code generator has
a better idea of how big the relocation table needs to be.
The sqlite3VdbeMakeLabel() routine now takes a Parse* parameter instead of
Vdbe*.

FossilOrigin-Name: 4a0929ac76d8aa5dd65eac3b83d6bbf41e505e01d175ca0fb2b19ba02d439415

src/sqliteInt.h

@@ -3069,6 +3069,7 @@ struct Parse {
   int iSelfTab;        /* Table associated with an index on expr, or negative
                        ** of the base register during check-constraint eval */
   int nLabel;          /* Number of labels used */
+  int nLabelAlloc;     /* Number of slots in aLabel */
   int *aLabel;         /* Space to hold the labels */
   ExprList *pConstExpr;/* Constant expressions */
   Token constraintName;/* Name of the constraint currently being parsed */