Figure out why variable template expressions are inconsistent with variable replacement

The following L# code:
```
grab io

number temperature = 98.4
io.log('Temperature set: `temperature`')
```

**Should** produce the following output:
```
Temperature set: 98.4
```

But it will sometimes produce the following output:
```
Temperature set: `temperature`
```

This means that the variable template expression intercept isn't working sometimes. This may be due to a couple reasons:
1. The variable is not stored in the `LSharpStack` by the time the variable template expression is executed
2. The stack is executing things in the wrong order

This can be determined by building the L# with the `-d` or `--debug` flag and observing the compiler debug messages.