This is an alternative to 'make integration_test',
with the following advantages:
* Tests run in Docker, so no bootstrap is necessary.
* Tests are hermetic and can run in parallel.
* Test against different flavors just by setting a flag.
* Failing tests are retried to see if they are flaky.
* A failed test will be recorded for later inspection, while the script
continues to run other tests.
* A test that takes too long will be considered stuck and retried.
There's plenty of room for improvement, but now that we have something
in a more readable language than Makefile, we can iterate.
Switch to using go install. Leads to faster and cleaner builds.
go install directly installs the binaries into $VTROOT/bin directly
because $GOPATH==$VTROOT. It also intalls intermediate libraries under
pkg, which results in reuse.
There is also no more clutter in the source dirs: cleaner .gitignore.
Numbered pool now accepts a purpose when locking resources,
and reports it as part of the error if it's in use.
Also dropping vttopo from Makefile and .gitignore.