Earlier detection of corruption in sqlite3VdbeRecordCompare() in order to

avoid a potential buffer overread.

FossilOrigin-Name: 28ddecff044dbc2dff50a7d8406ab67dfe06587f

src/vdbeaux.c

@@ -3434,6 +3434,7 @@ int sqlite3VdbeRecordCompare(
   }else{
     idx1 = getVarint32(aKey1, szHdr1);
     d1 = szHdr1;
+    if( d1>(unsigned)nKey1 ) return 1;  /* Corruption */
     i = 0;
   }