dillon1000/react

Fix temporaries accessed outside of their defining scope

Fixed a bug identified in repro cases earlier in the stack. The case is where 
some later value is composed of several values, say A and B, where A is an 
identifier that is reassigned within B. Also, the mutable range of B surrounds 
the evaluation of A. In this case, the reference to A gets lowered to a 
temporary (say a t0 = LoadLocal A), and that temporary is created within the 
reactive scope for B. 

PropagateScopeDependencies bypasses LoadLocal indirections, and considers the 
reference to the temporary (t0) as if it was a reference to the identifier (A). 
That breaks the whole reason we lower Identifiers to temporaries - to preserve 
evaluation order. 

This PR fixes the bug by promoting temporaries to names values if they are 
referenced outside their defining scope. So, the reference to t0 stays a 
reference to t0, which correctly preserves the value of A at the right point in 
time. 

This is all much easier to see in the new test case.