Flank: Outcome incorrectly set by Flank

[bootstraponline]

Describe the bug

A clear and concise description of what the bug is.

[task 2020-07-23T20:29:15.152Z] ┌─────────┬──────────────────────┬──────────────────────────────────────────┐
[task 2020-07-23T20:29:15.153Z] │ OUTCOME │      MATRIX ID       │               TEST DETAILS               │
[task 2020-07-23T20:29:15.153Z] ├─────────┼──────────────────────┼──────────────────────────────────────────┤
[task 2020-07-23T20:29:15.153Z] │  flaky  │ matrix-1vj2pt9wih182 │ 1 test cases failed, 106 passed, 2 flaky │
[task 2020-07-23T20:29:15.153Z] └─────────┴──────────────────────┴──────────────────────────────────────────┘

FTL confirmed the matrix outcome is actually failure. Flank reported flaky.

Let's diagram the Flank outcome setting logic with PlantUML in addition to fixing this bug.

Expected behavior

A clear and concise description of what you expected to happen.

I expected the outcome to match the FTL outcome (failure).

Details (please complete the following information):

Have you tested on the latest Flank snapshot?

Post the output of flank --version.

Flank v20.07.0

Additional context

Add any other context about the problem here.

https://firebase-community.slack.com/archives/C72V6UW8M/p1595539705001900

[pawelpasterz]

The logic that flank needs to reflect:

| Case | Outcome | Exit code |
| ------------- | :-------------: | :----------: |
| at least one test failed | failed | 1 |
| no failed test but at least 1 flaky | flaky | 0 |
| no failed and no flaky | success | 0 |

[pawelpasterz]

gcloud output

at least one test failed

no failed test but at least 1 flaky

no failed and no flaky

[pawelpasterz]

flank output

at least one test failed

no failed test but at least one flaky EDIT: below outcome is Corner Case

no failed and no flaky

What needs to be fixed:

• the failed test always means failed outcome, regardless of others being flaky (currently flaky tests obscure failed ones)
• flaky tests mean flaky outcome but with success exit code (currently exit code is 0 but status is success)
• optional: do we want to change the naming of the outcome? (ex. failure -> failed) cc @jan-gogo

[bootstraponline]

• do we want to change the naming of the outcome?

for naming, let's match gcloud.

[pawelpasterz]

no failed test but at least one flaky EDIT: below outcome is Corner Case

Above is a corner case that needs to be resolved in a separate issue (#918). It requires to check flank API calls with gcloud's.
Originally described bug to be resolved in #917

[pawelpasterz]

@rpappalax
Fix in review #917. Please let me know immediately if you will encounter a similar issue in the future. Please, keep in mind there is another issue found (thanks to your case 😄 ) we still need to investigate #918