[MC-237437] Inconsistency: Petrified oak slabs have dedicated models despite looking identical to oak slabs

Discovered while fixing MC-237435.

The bug

Certain blocks which are intended to appear identical in-game are defined differently. This report specificaly highlights the petrified oak slab, as its definition for this differs from other such blocks.

In most cases, if blocks are intended to appear identical, then the blockstates (and, if applicable, items) parameters will point to the same model file, rather than pointing to two different but visually identical model files. The petrified oak slab seems to disrupt this, as it has dedicated block models despite appearing identical to the oak slab.

List of such blocks:

Subject	blockstates/ target	models/item/ target
Waxed copper blocks	Respective unwaxed block	Respective unwaxed block
IInfested blocks	Respective non-infested block	Respective non-infested block
All double slabs	Respective full block*	N/A
8 layers of snow	snow_block.json	N/A
Petrified Oak Slab	petrified_oak_slab(_top).json	petrified_oak_slab.json

*excluding smooth stone, which has a dedicated different model

How to fix

The attached resource pack fully fixes this issue, as well as MC-237435 and the slab portion of MC-235694. A simpler pack that fixes only this issue can be attached instead if desired, however fixing all three issues is recommended.