Revert "MDEV-15778: Remove packed attr from omt_ and subtree_ classes"

This reverts commit 1735fa34.

storage/tokudb/ft-index/util/omt.h

@@ -181,7 +181,7 @@ class subtree_templated {
         paranoid_invariant(index != NODE_NULL);
         m_index = index;
     }
-} ;
+} __attribute__((__packed__,aligned(4)));
 
 template<>
 class subtree_templated<true> {
@@ -238,7 +238,7 @@ class subtree_templated<true> {
     inline void disable_bit(void) {
         m_bitfield &= MASK_INDEX;
     }
-} ;
+} __attribute__((__packed__)) ;
 
 template<typename omtdata_t, bool subtree_supports_marks>
 class omt_node_templated {
@@ -251,7 +251,7 @@ class omt_node_templated {
     // this needs to be in both implementations because we don't have
     // a "static if" the caller can use
     inline void clear_stolen_bits(void) {}
-} ;
+} __attribute__((__packed__,aligned(4)));
 
 template<typename omtdata_t>
 class omt_node_templated<omtdata_t, true> {
@@ -288,7 +288,7 @@ class omt_node_templated<omtdata_t, true> {
         this->unset_marked_bit();
         this->unset_marks_below_bit();
     }
-} ;
+} __attribute__((__packed__,aligned(4)));
 
 }