Remove too_slow_to_test flag

This flag was added to deal with inefficiencies of Icehouse. This
patch removes flag as it's not used in post-Icehouse.

Change-Id: I842dfe04725b2482399c0e95b54403fb82001645
see: If68c2b733358a98f56265b70c31366e6a9120dfa
3 files changed