[android] Enable Thread tests were possible.

[drodriguez]

Enable most of the Thread test for Android. The only tests that cannot
pass right now are the ones related to backtraces, which do not use the
Linux API backtrace and would need an specific implementation.

And while Android did not get pthread_getname_np until API 26, the low
level prctl(PR_GET_NAME) works with the same restriction as in Linux
(only 15 characters). With that change, the test about thread names also
passes in Android.

[spevans]

@swift-ci test

[drodriguez]

Removed a preprocessor flag that shouldn’t have been there.

@swift-ci please test

[spevans]

@swift-ci test

[drodriguez]

@millenomi: I think I have seen TestFileHandle.test_readWriteHandlers apparently lock up in several CI runs already. I wonder if the semaphore.wait(timeout: .distantFuture) can be reduced to a couple of seconds, to avoid locking up forever (probably breaking when result is not .success). Do you mind me doing that change? It will still fail, but at least the rest of the test suite will run, and the CI machine will not be hold for that long. Do you have a good timeout? 10 seconds?

[drodriguez]

@swift-ci please test linux platform

[millenomi]

There is an issue in libdispatch that is being tracked, but the wait kinda needs to match Darwin's.

[spevans]

Would an alarm(600) in Testfoundation/main.swift act as a simple timout in that SIGALRM should terminate the tests after 10 minutes?

[drodriguez]

Is the libdispatch issue in a public tracker that I can follow? I don’t know what you refer with “match Darwin's”, but my proposal is changing the timeout for every platform. If I read the code correctly, this is writing and reading from a pipe, so the delays from reading/writing should be minimal, whatever the platform. I think the change will give us the same signal as we have now, but clearer (it will be the assert about the timeout), instead of a CI build killed because of such timeout. In any case, whatever you think is best.

[drodriguez]

@swift-ci please test linux platform

[drodriguez]

Rebased and applied the changes from DEPLOYMENT_TARGET_* to TARGET_OS_*.

@swift-ci please test

[drodriguez]

@swift-ci please test

[drodriguez]

Rebased to fix the conflicts in the test file.

@swift-ci please test

[drodriguez]

Rebasing to a recent master. Still passing tests in Linux and Android.

@spevans, @millenomi, @compnerd: some feedback? positive or negative? I'm trying to clean up my old “stuck” PRs.

@swift-ci please test Linux platform

[drodriguez]

@swift-ci please test Linux platform

[spevans]

LGTM