Linux unit tests crashes in ssh

[dkwingsmt]

The linux unit tests crashes when I run it on my cloud gLinux:

[----------] 3 tests from FlPlatformPluginTest
[ RUN      ] FlPlatformPluginTest.PlaySound
[       OK ] FlPlatformPluginTest.PlaySound (0 ms)
[ RUN      ] FlPlatformPluginTest.ExitApplication
[       OK ] FlPlatformPluginTest.ExitApplication (0 ms)
[ RUN      ] FlPlatformPluginTest.ExitApplicationDispose

(flutter_linux_unittests:3309376): Gtk-WARNING **: 11:27:22.393: cannot open display: 
[FATAL:flutter/fml/thread_local.cc(32)] Check failed: false. pthread_setspecific failed (22): Invalid argument
[1]    3309376 IOT instruction  ../out/host_debug_unopt/flutter_linux_unittests

which might be due to the fact that ssh doesn't come with a display device.

Reproduction:

• Ssh into the cloudtop gLinux Open a terminal on Linux.
• Check out the commit 88baf62f1e66e973e919faef7d80fb1a4c3ef90c on the engine
• Compile and run ../out/host_debug_unopt/flutter_linux_unittests

Bisect shows that the first bad commit is flutter/engine#47713 by @gspencergoog.

If our guess is correct, then we can skip or even fail the test when there's no device, but crashing should still be avoided.

[dkwingsmt]

Just tested it today and flutter_linux_unittests crashes in the same way when I run it a desktop environment. I ran it in a terminal on gLinux. Engine rev 6810c9a57460524b985455d1aa9f9f50b01d1436

[flutter-triage-bot]

This issue is assigned to @gspencergoog but has had no recent status updates. Please consider unassigning this issue if it is not going to be addressed in the near future. This allows people to have a clearer picture of what work is actually planned. Thanks!