Const support more ops

[orklah]

This PR should solve #4739

[orklah]

I'm quite confused.

First thing, seems like bitwise or is already working, but I don't see why yet, it doesn't seem to be handled where I am. Plus, I don't get why the other two bitwise operations are not supported the same way.

Second thing is that an union between TLiteralInt(0) and TPositiveInt seems to be displayed as int|positive-int. I'm pretty sure this issue was fixed not long ago (multiple int not merging), maybe this is more localized than I thought

Third thing is that I broke some attribute test. I'm not sure how

I'll continue checking those

[orklah]

I think this should be ok now.

I changed a lot more than I thought I would:

• Fixed arithmetic operations and tests for pow/exponent. The symbol is **, not ^
• Added shift operations and some bitwise operations to arithmetics
• Changed positive-int to int in tests. I'm pretty sure it's because those are LiteralInt being calculated in arithmetics.

[muglug]

Thanks, this is awesome!