Add overhead time to junit test case report

[jan-goral]

Fixes #557

Checklist

• Unit tested
• release_notes.md updated

[bootstraponline]

awesome!

[jan-goral]

Hey @bootstraponline there is one think to consider here.
Our new junit report is uploaded to bucket only when option smart-flank-gcs-path is used. That means to use smart sharding correctly we need to run flank twice with smart-flank-gcs-path. First run will generate and upload correct report so second run can use it to properly calculate shard times. I it correct approach? Or maybe new junit report should be uploaded always, no matter if smart-flank-gcs-path used or not.

[jan-goral]

Second thing is that test suites names in junit report may not be unique so method mergeTestTimes here may not work correctly. For now I have not idea how to specify unique names to identify same suites between two test runs. But I guess that we can adjust implementation to omit suite names matching and base only on testcase names (and class names) from all suites. But them also may not be unique if user will add additional test apks where both contains same test name. Do you have any suggestions?

[codecov-io]

Codecov Report

Merging #684 into master will increase coverage by 0.10%.
The diff coverage is 81.81%.

@@             Coverage Diff              @@
##             master     #684      +/-   ##
============================================
+ Coverage     77.30%   77.41%   +0.10%     
- Complexity      624      626       +2     
============================================
  Files           109      109              
  Lines          2529     2541      +12     
  Branches        360      361       +1     
============================================
+ Hits           1955     1967      +12     
  Misses          345      345              
  Partials        229      229              

[jan-goral]

I've decided to omit this call when not useLegacyJUnitResult cause new junit result (from api) does not favor success over failure nor error, so we don't need to override failed test cases times.

[pawelpasterz]

Hey! I think we can simplify this with this.sumByDouble { it.elapsedTime.millis() }. Let me know what do you think. Thanks!