CMake: add_tests(): do not oversubscribe mpi/thread tests

cmake/macros/macro_deal_ii_add_test.cmake

@@ -601,25 +601,10 @@ function(deal_ii_add_test _category _test_name _comparison_file)
         #
         set_tests_properties(${_test_full} PROPERTIES RUN_SERIAL TRUE)
 
-      elseif(NOT ENABLE_PERFORMANCE_TESTS)
+      elseif()
         #
-        # Limit concurrency of mpi tests. We can only set concurrency for
-        # the entire test, which includes the compiling and linking stages
-        # that are purely sequential. There is no good way to model this
-        # without unnecessarily restricting concurrency. Consequently, we
-        # just choose to model an "average" concurrency as one half of the
-        # number of MPI jobs.
-        #
-        if(_n_cpu GREATER 2)
-          math(EXPR _slots "${_n_cpu} / 2")
-          set_tests_properties(${_test_full} PROPERTIES PROCESSORS ${_slots})
-        endif()
-
-      else()
-        #
-        # In case ENABLE_PERFORMANCE_TESTS is set we limit the concurrency
-        # of performance tests to the number of specified mpi ranks times
-        # the number of specified threads.
+        # Limit concurrency of tests that run on multiple mpi ranks, or
+        # that explicitly spawn multiple worker threads.
         #
         set(_slots 1)
         if(_n_cpu GREATER 0)