Add system_ext_specific

The system_ext partition was created. So if java_sdk_library module is
installed to system_ext partition, .xml and .jar install path must be
changed to system_ext.

Bug: 143440787
Test: add system_ext_specific to java_sdk_module && make -j && check
system_ext parition

Change-Id: Ie0d0df426d4aa96ac89eb4215e7376eea3f03f54