Update the sqlite3ExprCompare() routine so that it does not think "? IS NOT TRUE" is the same as "? IS TRUE". Fix for [d3e7f2ba5b3].

FossilOrigin-Name: 99eba69b3a64741c69d167bf7a05dbe138c9e7faecc54a1b8d8220cb23902830
diff --git a/src/expr.c b/src/expr.c
index 4b37e55..2d41fc4 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -4862,6 +4862,7 @@
      && (combinedFlags & EP_Reduced)==0
     ){
       if( pA->iColumn!=pB->iColumn ) return 2;
+      if( pA->op2!=pB->op2 ) return 2;
       if( pA->iTable!=pB->iTable 
        && (pA->iTable!=iTab || NEVER(pB->iTable>=0)) ) return 2;
     }