Decide on where to place mbed specific host tests

[rwalton-arm]

In mbed-os? Near test cases that use them? Separate package? (clarify) -- Don't put mbed-specific tests into standalone greentea

[evedon]

Leave smbed specific host tests in mbed-os where they currently are

[Patater]

Leave smbed specific host tests in mbed-os where they currently are

That's my preference as well. That might or might work when we move to using standalone greentea from Mbed OS.

[rajkan01]

The ARMmbed/mbed-os#14755 changes updated host_test (reside inside mbed-os) to import host test framework python classes from standalone htrun. The host tests reside inside mbed-os works fine with those changes, so better to keep the host tests inside mbed-os, closing this issue