nolibc: KTAP output and test reports

[Thomas Weißschuh]

Hi Willy, Zhangjin,

after your recent discussions about the test output and report I
wondered if it would make sense to switch nolibc-test to KTAP output
format [0].

With this it would be possible to have a wrapper script run each
architecture test as its own test subcomponent.
A (K)TAP parser/runner could then directly recognize and report failing
testcases, making it easier to validate.

Also maybe we can hook it up into the regular kselftests setup and have
the bots run it as part of that.

The kernel even includes a header-only library to implement the format [1].
It also should be fairly easy to emit the format without a library.

Thomas

[0] Documentation/dev-tools/ktap.rst
[1] Documentation/dev-tools/kselftest.rst (Test harness)