#575 [HPI WG 340-B]Add test about multiple users in a HPI implmnt

[David Lee]

ALL

Somehow need to test that multiple users in an HPI
implementation see the same data.

See HPI B.01.01 specification, section 3.6.1, page 25,
first sentence. What constitutes a "user" may differ
in various Operating systems or HPI implementations.
But, for a Linux-based test suite, should use what is
'reasonable' for a Linux implementation. May also need
to consider race conditions.