fdo#44286 unittest fails in non-English locale

The recently committed unittest for fdo#44286
(https://gerrit.libreoffice.org/#/c/9781/) fails on a non-English locale:

$ LANG=fr_LU.UTF-8 make -rs CppunitTest_svl_qa_cppunit
[build CUT] svl_qa_cppunit
/home/master/src/libreoffice/workdirs/master/svl/qa/unit/svl.cxx:403:(anonymous
namespace)::Test::testFdo44286
equality assertion failed
- Expected: 1902-04-22
- Actual  : YYYY-04-DD

svl.cxx:403:Assertion
Test name: (anonymous namespace)::Test::testFdo44286
equality assertion failed
- Expected: 1902-04-22
- Actual  : YYYY-04-DD

Failures !!!
Run: 7   Failure total: 1   Failures: 1   Errors: 0


-- 
Lionel