Piotr Tabor a6b0375b7b
Travis: Reduce footprint of unit tests - so hopefully flakiness (#12350)
* ./tests: Remove legacy coverage collection code

The legacy tests/cover.test.bash script was not ./test script
compatible for a long time.

The following method of coverage collection works (also across
packages) and does not make all the test execution slower.

```
COVERDIR=coverage PASSES="build build_cov cov" ./test
go tool cover -html ./coverage/cover.out
```

* CI: Reduce duplicated coverage between different variants on Travis

We used to execute unit tests in 3 different jobs,
every time with --race detection and every time in 3 variants:1,2,4
CPUS.

The proposed change makes each of the jobs use different variant of
CPUS, and only 4-cpu variant is running with --race detection
(as the more-parallel variant is more likely to experience races),
2020-09-29 19:47:05 -07:00
..
2020-05-09 23:34:20 -07:00