[MCPE-164623] Certain invalid loot tables crash minecraft

How to reproduce

1. Download and open the attached world
2. Kill the pigs named "crash"

Expected behavior

Content log error informing you that conditions entries should be of type object, not string
Content log error informing you that functions entries should be of type object, not string
Content log error informing you that pools entries should be of type object, not string

Actual behavior
Game crashes

Relevant loot tables

crash1

{
   "pools": [
      {
         "entries": [],
         "conditions": ["crash"]
      }
   ]
}

crash2

{
   "pools": [
      {
         "entries": [
            {
               "type": "item",
               "name": "apple",
               "functions": ["crash"]
            }
         ]
      }
   ]
}

crash3

{
   "pools": [
      {
         "entries": [
            {
               "type": 0,
               "pools": "crash"
            }
         ]
      }
   ]
}