[Backport] Security bug 415397143

Manual cherry-pick of patch originally published at
https://sqlite.org/src/info/2adaee9aa90f280a:
Fix a bug in the NOT NULL/IS NULL optimization of check-in [cb94350185f555c3] that can cause invalid
data to be used for a column if that column has a CHECK constraint that includes the NOT NULL or
IS NULL operator. Problem discovered by the Chromium fuzzer. Never seen in the wild, as far as
anybody knows.

Original patch by drh.

Change-Id: Icd9963f14b35bb393e9b1269c0c74b8d30b225bb
Reviewed-on: https://codereview.qt-project.org/c/qt/qtwebengine-chromium/+/659331
Reviewed-by: Moss Heim <[email protected]>

Author: mibrunin

chromium/third_party/sqlite/src/amalgamation/sqlite3.c

@@ -96794,6 +96794,7 @@ case OP_MakeRecord: {
       zHdr += sqlite3PutVarint(zHdr, serial_type);
       if( pRec->n ){
         assert( pRec->z!=0 );
+        assert( pRec->z!=(const char*)sqlite3CtypeMap );
         memcpy(zPayload, pRec->z, pRec->n);
         zPayload += pRec->n;
       }
@@ -114745,11 +114746,11 @@ SQLITE_PRIVATE void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int
       assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
       assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );
       r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
-      sqlite3VdbeTypeofColumn(v, r1);
+      assert( regFree1==0 || regFree1==r1 );
+      if( regFree1 ) sqlite3VdbeTypeofColumn(v, r1);
       sqlite3VdbeAddOp2(v, op, r1, dest);
       VdbeCoverageIf(v, op==TK_ISNULL);
       VdbeCoverageIf(v, op==TK_NOTNULL);
-      testcase( regFree1==0 );
       break;
     }
     case TK_BETWEEN: {
@@ -114920,11 +114921,11 @@ SQLITE_PRIVATE void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int
     case TK_ISNULL:
     case TK_NOTNULL: {
       r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
-      sqlite3VdbeTypeofColumn(v, r1);
+      assert( regFree1==0 || regFree1==r1 );
+      if( regFree1 ) sqlite3VdbeTypeofColumn(v, r1);
       sqlite3VdbeAddOp2(v, op, r1, dest);
       testcase( op==TK_ISNULL );   VdbeCoverageIf(v, op==TK_ISNULL);
       testcase( op==TK_NOTNULL );  VdbeCoverageIf(v, op==TK_NOTNULL);
-      testcase( regFree1==0 );
       break;
     }
     case TK_BETWEEN: {