Adjust the sqlite3PagerDirectReadOk() routine (part of the

SQLITE_DIRECT_OVERFLOW_READ optimization) to use less code and to be
more easily testable.

FossilOrigin-Name: eed670ea2a9424f7df4eeb01c152fc38f7190a5e39aa891651b28dc91fcdc019

src/wal.c

@@ -3505,6 +3505,7 @@ static int walFindFrame(
         iRead = iFrame;
       }
       if( (nCollide--)==0 ){
+        *piRead = 0;
         return SQLITE_CORRUPT_BKPT;
       }
       iKey = walNextHash(iKey);