icu: un-break installation of Java extensions on Windows (rel. fdo#63756)

Linking libxml2 against ICU libraries has a nasty side effect:
The URE library javavm.dll links against URE libxml2.dll, which
is now linked against OOO icuuc53.dll; when a URE program, like
uno.exe, tries to load javavm.dll it fails because the OOO layer
"program" dir is not on PATH; this breaks the installation of Java
extensions.

Fix that by splitting up ICU libraries and putting the required ones
into URE layer.

(regression from 7515b1a90fac9e31733c0fdcc1156adadf0e6f99)

Change-Id: If98dd0357162cb632d9762cd2d20162de5eb1a52
(cherry picked from commit 057613c6864204ac5c09260e93a8f14cc9768b90)
Reviewed-on: https://gerrit.libreoffice.org/10500
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>