system_test was taking too long to run.

SPARSE_NORMAL_CHOLESKY with CXSparse on the fairly small
bundle adjustment problem used in system_test is too expensive
to be useful as a test. It takes up too much memory and time
making the test fail on client computers < 4G of RAM.

These tests have been deleted.

Change-Id: Id015671536afd7013f5b7d19c39d64c2748884ad