While the modifier state property in core's API is 16-bit, internally
ldml_processor supports the modifier flag LDML_KEYS_MOD_OTHER with a
value of `0x10000`, which requires widening the value (we match the
32-bit size of the KMX_DWORD value from KMX+).
Note: this is not yet well unit-tested.
Relates-to: #11072Fixes: #12057
- distinguish between unmapped and 0-length output strings
- don't do any processing for 0-length output strings
- no change to developer, that will be next
- remove a comment referencing transform=no
For: #9451
- lookup needs to handle either/neither/both cases for alt and ctrl
- and a bug in the test runner: would 'pass' if failed on exactly line 256 (0x100 & 0xFF == 0)
#7533