rename and move unit test

Author: polgreen

unit/Makefile

@@ -9,7 +9,6 @@ SRC = unit_tests.cpp \
 SRC += unit_tests.cpp \
        analyses/ai/ai_simplify_lhs.cpp \
        analyses/call_graph.cpp \
-       analyses/graph.cpp \
        analyses/does_remove_const/does_expr_lose_const.cpp \
        analyses/does_remove_const/does_type_preserve_const_correctness.cpp \
        analyses/does_remove_const/is_type_at_least_as_const_as.cpp \
@@ -23,6 +22,7 @@ SRC += unit_tests.cpp \
        solvers/refinement/string_refinement/sparse_array.cpp \
        solvers/refinement/string_refinement/union_find_replace.cpp \
        util/expr_cast/expr_cast.cpp \
+       util/disconnect_unreachable_nodes_in_graph.cpp \
        util/irep.cpp \
        util/irep_sharing.cpp \
        util/message.cpp \