The code to work around setlocale() mis-describing en_US as C ensured
that we didn't accept the C test-cases when the locale was really
en_US; but neglected to accept the en_US test-cases when the locale
really was en_US but was misdescribed as C. This lead to no tests
being run when the locale was en_US.
Tweak the logic of the test filtering to compare the wanted locale
against the system locale both when C is wanted and when it isn't.
Make the skip-messages a little more informative.
Pick-to: 6.2 6.1
Change-Id: I4e072e12819144b2941b87a5f486534047d9a579
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
a13942791d