PS-9293, PS-9328: Revert of fix for PS-7666: Assertion failure: fil0fil.cc:13097:fil_system->shard_by_id(id)->mutex_owned().

Reverted Percona Server's fix for PS-7666 as it became redundant
after Upstream's has fixed the problem in a different way.
See the Upstream's fix for bug#32819101 "ASSERTION FAILURE: FIL0FIL.CC:
12089:FIL_SYSTEM->SHARD_BY_ID(ID)->MUTEX_OWNED()" for details:

4a2cf86

Removed Percona's test case as well, as Upstream fix comes with one.

Author: dlenev

mysql-test/suite/innodb/r/drop_table_crash_debug.result

@@ -3207,10 +3207,7 @@ static bool fil_space_free(space_id_t space_id, bool x_latched) {
     rw_lock_x_unlock(&space->latch);
   }
 
-  shard->mutex_acquire();
   Fil_shard::space_free_low(space);
-  shard->mutex_release();
-
   ut_a(space == nullptr);
 
   return true;
@@ -4572,9 +4569,6 @@ dberr_t Fil_shard::space_delete(space_id_t space_id, buf_remove_t buf_remove) {
 
     mtr.commit();
 
-    DBUG_EXECUTE_IF("delete_crash", log_buffer_flush_to_disk();
-                    DBUG_SUICIDE(););
-
     /* Even if we got killed shortly after deleting the
     tablespace file, the record must have already been
     written to the redo log. */