Debug freezes

[KatieWoe]

While running fuzz test on phetsims/qa#297 I noticed that the window froze after ~20 min. Happened with another sim as well, so likely not specific to this sim.

[KatieWoe]

Per request of @jbphet I did a memory test under these same conditions. It started at 23.8 and after ten minutes was 34.8 and holding fairly steady. So that doesn't seem to be the issue.

[jbphet]

I ran fuzz testing on the debug version for over an hour on my Dell Win 10 machine in Chrome 72.0.3626.121 and did not hit a freeze. @KatieWoe - how about you see if you can duplicate it on whatever machine/browser you found it on while we're both on campus and I'll take a look at it then. Other than that, it seems like an unusual enough case (debug version and fuzz testing) that it shouldn't block publication.

[KatieWoe]

Seems to happen occasionally on sims in general when left long enough in this state. Moving to joist for reference and unassigning

[zepumph]

@KatieWoe is this still an issue you run into? Please assign me after responding.

[KatieWoe]

I don't often run tests for that long, so I'm not sure

[zepumph]

Ok thanks for letting me know.