- add a normalize_nfd() which takes a single codepoint
- temporarily keep ICU in actions_normalize.cpp and ldml_transforms.cpp
- expand wasm opts in unit tests
- always set to 0 for now (keep ICU around)
- set KMN_IN_LDML_TESTS in tests to keep ICU there for test and comparison
- add core_icu.cpp and put some utils there.
#9467