fix occasional Chromium BUS_ADRERR
fix occasional Chromium BUS_ADRERR

Chromium really likes its shared memory. I never actually saw a problem with the size of /dev/shm until trying to train an agent on KumbaKarate-v0, where a crash would happen fairly frequently. Increasing shared memory size appears to fix the issue, as many google searches would suggest.

For the record, the crash happened during a PNG screenshot capture. Here's the stack trace:

Received signal 7 BUS_ADRERR 7f8f346d6000
0 0x56168e9dcfb7 base::debug::StackTrace::StackTrace()
1 0x56168e9dcb2f base::debug::(anonymous namespace)::StackDumpSignalHandler()
2 0x7f8f54c75390 <unknown>
3 0x56168f011c30 sk_memset32()
4 0x56168efed94e SkPixmap::erase()
5 0x56168ef48621 SkBitmap::eraseColor()
6 0x56169075419b blink::ImageFrame::ZeroFillPixelData()
...

unixpickle/muniverse,unixpickle/muniverse,unixpickle/muniverse,unixpickle/muniverse