Cprover should have an `__enum_in_range` primitive

[danielsn]

It is currently difficult to use the --enum-range-check option, because it is hard to ensure in a harness that an enum is within range. IF there was a
__CPROVER_enum_is_in_range(e) primitive, we could use it like
__CPROVER_assume(__CPROVER_enum_is_in_range(e))
and
assert(__CPROVER_enum_is_in_range(e))

[feliperodri]

@hannes-steffenhagen-diffblue is there anyone currently working on this issue? Any updates?

[TGWDB]

See pull request here.

[TGWDB]

Fixed in #5808