feat(compiler): Implement constant propagation for template literals (#33139)

New take on #29716

## Summary
Template literals consisting entirely of constant values will be inlined
to a string literal, effectively replacing the backticks with a double
quote.

This is done primarily to make the resulting instruction a string
literal, so it can be processed further in constant propatation. So this
is now correctly simplified to `true`:
```js
`` === "" // now true
`a${1}` === "a1" // now true
```

If a template string literal can only partially be comptime-evaluated,
it is not that useful for dead code elimination or further constant
folding steps and thus, is left as-is in that case. Same is true if the
literal contains an array, object, symbol or function.

## How did you test this change?

See added tests.