Support for assume() and assert() functions in Chiron

[lahiri-phdworks]

Is your feature request related to a problem? Please describe.
I think adding the support for assume() and assert() functions directly in the .tl file make verification and testing tasks more comprehensive.

Describe the solution you'd like
Change to the AST for adding these function support.

Describe alternatives you've considered
None

Additional context
Requesting implementation changes.