These blocks cannot normally be broken in survival, which is a likely explanation for the absence of loot tables for these blocks. However, the /setblock command with "destroy" can be used to simulate a "legitimate" breaking of such blocks (as can be seen with the example shown of breaking a stone block to produce cobblestone). As no such loot tables exist for these blocks, mapmakers are limited as to what can be done with these blocks, as it may be desirable for a block to be completely unbreakable by players but yield an item when broken via command.
Confirmed to be affected:
minecraft:bedrock
minecraft:end_portal_frame
minecraft:end_portal
minecraft:end_gateway
minecraft:barrier
Untested, but likely also affected:
minecraft:command_block
minecraft:chain_command_block
minecraft:repeating_command_block
minecraft:structure_block
minecraft:jigsaw
Relates to MC-157395.