Extended external semaphore import/export tests to cover more handle types

[shajder]

Due to discussion from #2542

[shajder]

Any chance you could "git mv" the prior test_external_semaphore_sync_fd.cpp to test_external_semaphore_handle_types.cpp? I think that will let us see the deltas between the two files vs. treating them as entirely separate.

Actually I did, for some reason history get lost (probably too many operations in one commit)