Removed android.debug.JNITest from preloaded-classes

android.debug.JNITest class no longer exists in this
project. This patch updates preloaded-classes accordingly
to avoid spurious warning during boot.

Change-Id: Ia4a5a1858f6c87fbc594a623adb95454334361ea
Signed-off-by: Ashok Bhat <ashok.bhat@arm.com>