Remove the vdbeRecordCompareLargeHeader function. Fix some other details.

FossilOrigin-Name: 3861e853105cb8da344c7eebd2e455622b26395e
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index eece50f..a368b96 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1586,14 +1586,17 @@
 **
 ** This structure holds a record that has already been disassembled
 ** into its constituent fields.
+**
+** The r1 and r2 member variables are only used by the optimized comparison
+** functions vdbeRecordCompareInt() and vdbeRecordCompareString().
 */
 struct UnpackedRecord {
   KeyInfo *pKeyInfo;  /* Collation and sort-order information */
   u16 nField;         /* Number of entries in apMem[] */
   char default_rc;    /* Comparison result if keys are equal */
   Mem *aMem;          /* Values */
-  int r1;
-  int r2;
+  int r1;             /* Value to return if (lhs > rhs) */
+  int r2;             /* Value to return if (rhs < lhs) */
 };