Avoid particular includes in NDK

We need to expose ulocdata_getCLDRVersion in ulocdata.h, but
avoid exposing other headers.
It helps avoid exposing another @IntraCoreApi.

Bug: 139480281
Test: ./tools/icu4c_srcgen/generate_ndk.py
Change-Id: I9eca72fcd59b315e943f157cf9f0eb7e39d78dd9
2 files changed