Allow NULL JNI arguments for length 0 memcpys.
Allow NULL JNI arguments for length 0 memcpys.

Bug 10393546.

Change-Id: Ifaba4481e5b356c3e85a32525e6007e35036fcd1

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst