RCO too eager, interferes with explicate

[jsiek]

For example,

print(42 if not (x == y) else 5)

compiles to more efficient code if RCO doesn't create a temporary for x == y.

[elavoie]

As discussed here: #179 (comment)

This can be solved by partially evaluating the not operation before the RCO pass, resulting in:

print(42 if x != y else 5)