Add two tests for decoding IDNs when they encode values outside Unicode
(> 0x110000).
"xn--5p32g" decodes to "a" (all ASCII) before QTBUG-95577 got fixed.
"xn--400595c" decodes to the same value as "xn--097c" after the above
mentioned bug got fixed. This test is currently failing.
Task-number: QTBUG-95689
Pick-to: 6.2
Change-Id: Icab55c41e0233b34d57e38232fa90ac42f35a50a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>