Remove tests from external/apache-harmony

These tests are already replicated (sometimes in modified form) in the libcore
tree in various places.  I compared their contents and couldn't find any
significant missing pieces from these, so just get rid of these instead of
including them.

Bug: 4483710
Test: cts -m CtsLibcoreTestCases
Change-Id: Id1cc89685e2a3cfd2f69e832beb214487ba53b3d