Sprite execution order incompatibility causes layering issues in this project

[kchadha]

Expected Behavior

https://scratch.mit.edu/projects/73724746/ should behave the same in 2.0 and 3.0.

Actual Behavior

This project does not have the mountains in the correct layer when imported into 3.0. I think this is an execution order issue as the sprites follow the model of go to front followed by go back [n] layers. The resulting layer for the sprite in question depends on when the sprites code is executed in comparison to other sprites.

Found by @carljbowman in a smoke test on 08/17/18.

[thisandagain]

@rschamp This might be a good one for @mzgoddard to take a look at.

[LiFaytheGoblin]

Can also be observed in 94795454

[kchadha]

It looks like seeing this project in editor mode has an effect on the severity of the bug.

Here are two more projects made to help debug the original:

https://scratch.mit.edu/projects/293000927/
https://scratch.mit.edu/projects/293002304/