Faster response to sqlite3_interrupt() in the OP_IntegrityCk and OP_Count

opcodes.

FossilOrigin-Name: bf875dc59909f9c22f7c1fc843bc4d9e5d97af5cb4ef43c4fa1d566ddfdeaacb

src/btreeInt.h

@@ -685,6 +685,7 @@ struct IntegrityCk {
   int v1, v2;       /* Values for up to two %d fields in zPfx */
   StrAccum errMsg;  /* Accumulate the error message text here */
   u32 *heap;        /* Min-heap used for analyzing cell coverage */
+  sqlite3 *db;      /* Database connection running the check */
 };
 
 /*