With puppeteer, "Failed to launch chrome" error

Hi,

**My config:**
I'm running Backstop on Windows 10, npm@5.6.0, and puppeteer is on version 1.18.0.

**My problem:**
Some of the scenarios seem to be running, but after a few tests run (out of over 500), this error appears:
```
COMMAND | Command "test" ended with an error after [34.859s]
COMMAND | Error: Failed to launch chrome!
[0819/161753.662:FATAL:feature_list.cc(237)] Check failed: !g_initialized_from_acce
ssor.
Backtrace:
ovly_debug_event [0x00007FFD660AD512+15381554]
ovly_debug_event [0x00007FFD660ACAF2+15378962]
ovly_debug_event [0x00007FFD660C0413+15459123]
ovly_debug_event [0x00007FFD660AF55E+15389822]
ovly_debug_event [0x00007FFD6594FF71+7659153]
ovly_debug_event [0x00007FFD6602AB21+14846529]
ovly_debug_event [0x00007FFD6602AA8A+14846378]
ovly_debug_event [0x00007FFD66055958+15022200]
ovly_debug_event [0x00007FFD6602A332+14844498]
ovly_debug_event [0x00007FFD66054DE6+15019270]
ovly_debug_event [0x00007FFD66054CBE+15018974]
ovly_debug_event [0x00007FFD66054AF4+15018516]
ChromeMain [0x00007FFD652011B6+286]
Ordinal0 [0x00007FF6DCE72767+10087]
Ordinal0 [0x00007FF6DCE7182B+6187]
GetHandleVerifier [0x00007FF6DCF74AD2+663890]
BaseThreadInitThunk [0x00007FFDD74C7BD4+20]
RtlUserThreadStart [0x00007FFDD79CCE71+33]

TROUBLESHOOTING: https://github.com/GoogleChrome/puppeteer/blob/master/docs/trouble
shooting.md

at onClose (C:\workspace\uibackstopautomationtests\node_modules\puppeteer\lib\L
auncher.js:340:14)
at ChildProcess.helper.addEventListener (C:\workspace\uibackstopautomationtests
\node_modules\puppeteer\lib\Launcher.js:330:60)
at emitTwo (events.js:131:20)
at ChildProcess.emit (events.js:214:7)
at Process.ChildProcess._handle.onexit (internal/child_process.js:198:12)
Error: Failed to launch chrome!
[0819/161753.662:FATAL:feature_list.cc(237)] Check failed: !g_initialized_from_accessor.
Backtrace:
ovly_debug_event [0x00007FFD660AD512+15381554]
ovly_debug_event [0x00007FFD660ACAF2+15378962]
ovly_debug_event [0x00007FFD660C0413+15459123]
ovly_debug_event [0x00007FFD660AF55E+15389822]
ovly_debug_event [0x00007FFD6594FF71+7659153]
ovly_debug_event [0x00007FFD6602AB21+14846529]
ovly_debug_event [0x00007FFD6602AA8A+14846378]
ovly_debug_event [0x00007FFD66055958+15022200]
ovly_debug_event [0x00007FFD6602A332+14844498]
ovly_debug_event [0x00007FFD66054DE6+15019270]
ovly_debug_event [0x00007FFD66054CBE+15018974]
ovly_debug_event [0x00007FFD66054AF4+15018516]
ChromeMain [0x00007FFD652011B6+286]
Ordinal0 [0x00007FF6DCE72767+10087]
Ordinal0 [0x00007FF6DCE7182B+6187]
GetHandleVerifier [0x00007FF6DCF74AD2+663890]
BaseThreadInitThunk [0x00007FFDD74C7BD4+20]
RtlUserThreadStart [0x00007FFDD79CCE71+33]

TROUBLESHOOTING: https://github.com/GoogleChrome/puppeteer/blob/master/docs/troubleshooting.md

at onClose (C:\workspace\uibackstopautomationtests\node_modules\puppeteer\lib\Launcher.js:340:1
4)
at ChildProcess.helper.addEventListener (C:\workspace\uibackstopautomationtests\node_modules\pu
ppeteer\lib\Launcher.js:330:60)
at emitTwo (events.js:131:20)
at ChildProcess.emit (events.js:214:7)
at Process.ChildProcess._handle.onexit (internal/child_process.js:198:12)

```

**Solutions I've tried:**
1. My package.json already has `"engineOptions": { "args": ["--no-sandbox"]}`
1. Tried plugging in `ignoreDefaultArgs: ['--disable-extensions']` to my `engineOptions` after seeing https://github.com/GoogleChrome/puppeteer/blob/master/docs/troubleshooting.md#chrome-headless-doesnt-launch-on-windows but it didn't stop the error.
1. In addition, also tried plugging in `['--disable-setuid-sandbox']` to args the first attempt above, and that also did not work.

**Similar issues:**
I also took a look at https://github.com/garris/BackstopJS/issues/827 and https://github.com/garris/BackstopJS/issues/803, and neither of these seem to apply. These tests were running fine a few weeks before, and I haven't changed any of the files since then, but not sure what is the difference now.

Would really appreciate any help!