Solang does not use all Solidity Panic codes

[xermicus]

While implementing of #1449, it became apparent that Solang does not use all the Panic codes Solidity knows. Maybe this is fine because for our currently supported targets, it doesn't make sense to use them. But it is a hint that our codegen could produce different code from what's actually expected and should be investigated further.

Currently never used:

• EnumCastOob
• StorageBytesEncodingIncorrect
• OutOfMemory