Reveal the call trace of failed test cases which run in executors

Currently, the fails in testTcpSocketKeepalives are triggered by
fail() inside the executor, which is hiding the actual call trace
but only message remains. And it made the fail case hard to
debug.

So this commit is to bubble up the Exception by using a custom
functional interface.

Bug: 123987272
Test: 1. atest FrameworksNetTests
      2. manually fail the test case and see the call trace

Change-Id: I125e673938a5e9d1de86f83c1a732227a4bd3207