Update.
* iconvdata/TESTS: Name new tests.
* iconvdata/testdata/CP1250: New file.
* iconvdata/testdata/CP1250..UTF8: New file.
* iconvdata/testdata/CP1251: New file.
* iconvdata/testdata/CP1251..UTF8: New file.
* iconvdata/testdata/CP1252: New file.
* iconvdata/testdata/CP1252..UTF8: New file.
* iconvdata/testdata/CP1253: New file.
* iconvdata/testdata/CP1253..UTF8: New file.
* iconvdata/testdata/CP1254: New file.
* iconvdata/testdata/CP1254..UTF8: New file.
* iconvdata/testdata/CP1255: New file.
* iconvdata/testdata/CP1255..UTF8: New file.
* iconvdata/testdata/CP1256: New file.
* iconvdata/testdata/CP1256..UTF8: New file.
* iconvdata/testdata/CP1257: New file.
* iconvdata/testdata/CP1257..UTF8: New file.