Tests: skip test cases more related to ICU than mlocale

Many test cases verify ICU does its job as expected. This is not our
focus nowadays while it requires to update testcases whenever ICU
changes (as ICU continuously improves its job especially in case of
"exotic" languages).

This commit excludes those test cases where such changes can be
expected. Full test set can be included by #defining
ALSO_VERIFY_ICU_DOES_ITS_JOB_AS_WE_EXPECT

My aim was to (1) have the patch as compact as possible while (2) having
the limited test set as the default configuration - hence the inversed
pattern which the reader's eyes quicky adapt to IMO :)

Signed-off-by: Martin Kampas <martin.kampas@tieto.com>