Add apache-xml for all modes for consistency

apache-xml is part of the normal device classpath so should
be present for all modes for consistency.

Bug: 120526172
Test: build / treehugger
Test: vogar --mode host libcore/luni/src/test/java/libcore/java/util/prefs/OldAbstractPreferencesTest.java
Test: vogar --mode device libcore/luni/src/test/java/libcore/java/util/prefs/OldAbstractPreferencesTest.java
Change-Id: Ia169410a9a58da505bd70b6289ff20d02ab9feb9
1 file changed