In b28613c2 (Add StrictUnicode mode) I modified TestEntry to have
.strictUnicodeN and .strictUnicodeY fields and adjusted X to set them
both to true by default. However I missed to adjust Xloosy, which
started to return TestEntry with both .strictUnicodeN=.strictUnicodeY=false
which effectively disabled running test entries defined via Xloosy.

-> Fix that by reusing X in Xloosy implementation.

This brings in unnoticed test failures with structs and strings:

    --- FAIL: TestDecode (0.03s)
        --- FAIL: TestDecode/[]ogórek.foo{"Qux",_4}/StrictUnicode=y/"((S\"Foo\"\nS\"Qux\"\nS\"Bar\"\nI4\ndl." (0.00s)
            ogorek_test.go:594: decode:
                have: []interface {}{map[interface {}]interface {}{ogórek.ByteString("Bar"):4, ogórek.ByteString("Foo"):ogórek.ByteString("Qux")}}
                want: []interface {}{map[interface {}]interface {}{"Bar":4, "Foo":"Qux"}}
        --- FAIL: TestDecode/[]ogórek.foo{"Qux",_4}/StrictUnicode=y/"((U\x03FooU\x03QuxU\x03BarK\x04dl." (0.00s)
            ogorek_test.go:594: decode:
                have: []interface {}{map[interface {}]interface {}{ogórek.ByteString("Bar"):4, ogórek.ByteString("Foo"):ogórek.ByteString("Qux")}}
                want: []interface {}{map[interface {}]interface {}{"Bar":4, "Foo":"Qux"}}
    --- FAIL: TestEncode (0.11s)
        --- FAIL: TestEncode/[]ogórek.foo{"Qux",_4}/StrictUnicode=y/proto=0 (0.00s)
            ogorek_test.go:670: encode:
                have: "((VFoo\nVQux\nVBar\nI4\ndl."
                want: "((S\"Foo\"\nS\"Qux\"\nS\"Bar\"\nI4\ndl."
        --- FAIL: TestEncode/[]ogórek.foo{"Qux",_4}/StrictUnicode=y/proto=1 (0.00s)
            ogorek_test.go:670: encode:
                have: "((X\x03\x00\x00\x00FooX\x03\x00\x00\x00QuxX\x03\x00\x00\x00BarK\x04dl."
                want: "((U\x03FooU\x03QuxU\x03BarK\x04dl."
        --- FAIL: TestEncode/[]ogórek.foo{"Qux",_4}/StrictUnicode=y/proto=2 (0.00s)
            ogorek_test.go:670: encode:
                have: "\x80\x02((X\x03\x00\x00\x00FooX\x03\x00\x00\x00QuxX\x03\x00\x00\x00BarK\x04dl."
                want: "\x80\x02((U\x03FooU\x03QuxU\x03BarK\x04dl."

because in that test data are prepared to auto strings mode and started
to fail with StrictUnicode=y. Fix that by adjusting that test to run in
StrictUnicode=n mode only.