Oz + Exceptions is infact increasing code size

To reduce size, I tried to use `-Oz` instead of `-O3` which we were doing early. For build with `-sDISABLE_EXCEPTION_CATCHING=1` we got positive results with considerable size reduction of wasm and very little size increment of support js. But for build with `-sDISABLE_EXCEPTION_CATCHING=0` we didn't get any size reduction for wasm and support js size increased from 3.7 MB to 10 MB !! Upon seeing the diff, we can see many entries of type below added :

```
var = (Module[""]) = function () { ... }
```

We are using same list of exported functions for both builds so we are unable to understand this significant increase in js size without any decrement in wasm size.