Merge "Update JNI code in preparation for ICU 59 switching to C++11 char16_t." am: 0f3d90eec8  -s ours am: cd53e91851 am: 28f67840c6
am: 9337ec6e2d  -s ours

Change-Id: I8abc0ead892281b576ea1663e5c73a9ebd1f905f