DMN 1.4 - 1150-boxed-conditional

[StrayAlien]

No description provided.

[opatrascoiu]

@StrayAlien They look good to me.

We should probably add a few more:

• then and else branches do not return the same type (e.g. one number the other one string) and typeRefs (e.g. on TConditional or branches) to check for type mismatch.
• nested if then else

[StrayAlien]

Thanks @opatrascoiu - fair call. I guess similar tests could be added to the other new boxed expression as well. I was going to leave the typeRef checking as a follow on PR to the 'domain' checking PR, but, it'll not hurt to get them in here. Thanks.

[SimonRinguette]

I validated these tests

[baldimir]

If we need more tests, they could be created as a separate PR to not hold these.