[aat.kerx] Remove kerx subtable boundary enforcement

Have not encountered fonts needing this, but same reasoning as
for morx (see previos commit.)

src/hb-aat-layout-kerx-table.hh

@@ -926,12 +926,6 @@ struct KerxTable
       if (reverse)
 	c->buffer->reverse ();
 
-      /* See comment in sanitize() for conditional here. */
-      if (i < count - 1)
-	c->sanitizer.set_object (*st);
-      else
-	c->sanitizer.reset_object ();
-
       ret |= st->dispatch (c);
 
       if (reverse)
@@ -943,7 +937,6 @@ struct KerxTable
       st = &StructAfter<SubTable> (*st);
       c->set_lookup_index (c->lookup_index + 1);
     }
-    c->sanitizer.reset_object ();
 
     return ret;
   }
@@ -962,24 +955,10 @@ struct KerxTable
     unsigned int count = thiz()->tableCount;
     for (unsigned int i = 0; i < count; i++)
     {
-      c->reset_object ();
-      if (unlikely (!st->u.header.sanitize (c)))
-	return_trace (false);
-      /* OpenType kern table has 2-byte subtable lengths.  That's limiting.
-       * MS implementation also only supports one subtable, of format 0,
-       * anyway.  Certain versions of some fonts, like Calibry, contain
-       * kern subtable that exceeds 64kb.  Looks like, the subtable length
-       * is simply ignored.  Which makes sense.  It's only needed if you
-       * have multiple subtables.  To handle such fonts, we just ignore
-       * the length for the last subtable. */
-      if (i < count - 1)
-	c->set_object (*st);
-
       if (unlikely (!st->sanitize (c)))
 	return_trace (false);
       st = &StructAfter<SubTable> (*st);
     }
-    c->reset_object ();
 
     return_trace (true);
   }