Revert "Add legacy inlines for locale aware APIs."

We can't really add these to the unified headers yet since we're
still using the old headers as well, and libandroid_support needs to
work with both. These functions are already defined in
libandroid_support, so when using unified headers we'll get duplicate
definitions.

This was only going to be a temporary solution anyway. Instead we'll
just rely on libandroid_support (and eventually its rewrite) to handle
these.

This reverts commit 6576a374.

Test: ./tools/update_headers.py && make ndk && make native
      # Copied into working directory for unified headers NDK work.
      ndk/checkbuild.py
      ndk/run_tests.py --force-unified-headers
Bug: None

Change-Id: I5762e815e2030c89d7f2540df08dd67b6c2d10a5