Add `check` target as an alias to the `test` target

This is just a convenience target alias (`check` is for instance the
classic test suite target name used by `autotools`)

CMakeLists.txt

@@ -329,6 +329,10 @@ add_custom_target(all_unit_tests
   DEPENDS unit_tests mpi_unit_tests
 )
 
+add_custom_target(check
+  DEPENDS test
+  )
+
 add_custom_target(test
   DEPENDS run_all_unit_tests
   )