dillon1000/react

[rhir] Patch for reactive computed loads

We need to check reactivity of both the operand and its resolved source (if 
operand is produced by a LoadLocal / PropertyLoad / ComputedLoad). 

Both the operand and its source can have reactivity. 

e.g. 

```js 

const o = makeObject(); // source has no reactivity 

const x = o[props.x];   // x is reactive 

```