[flutter_tools] add debugging to ios/core_devices.dart

[christopherfujino]

Add debugging for #141892 to detect when the temp file mysteriously disappears after running devicectl.

[christopherfujino]

FYI @eliasyishak, please let me know if you see this test fail after this lands

[vashworth]

Looks like you hit the issue in presubmit: https://ci.chromium.org/ui/p/flutter/builders/try/Mac%20tool_integration_tests_4_4/32144/overview

It doesn't print out the print trace, only the StateError, probably because the command wasn't verbose?

[christopherfujino]

It doesn't print out the print trace, only the StateError, probably because the command wasn't verbose?

ahh, you're right, and the whole point of this test is to verify the non-verbose output.

[christopherfujino]

Ok, pushed a change commenting out every test except the one in question, and running it 100 times. hopefully we'll get a repro with the full stacktrace.

[christopherfujino]

Ok, pushed a change commenting out every test except the one in question, and running it 100 times. hopefully we'll get a repro with the full stacktrace.

for whatever reason, running just the test in question 100x across several builds did not yield the error (it might have to do with running all the tests sequentially), so I moved the interesting prints from trace to error, which the test expectation should print when it fails.

[andrewkolos]

RSLGTM