Fixing initial value for interval set parameters.

When tuning Kokkos kernels, we need to use the initial value of the
variable, which is (supposed to be) given to us by Kokkos.

src/apex/apex_kokkos_tuning.cpp

@@ -390,11 +390,23 @@ void handle_start(const std::string & name, const size_t vars,
         for (size_t i = 0 ; i < vars ; i++) {
             auto id = values[i].type_id;
             Variable* var{getSession().outputs[id]};
+            /* If it's a set, the initial value can be a double, int or string
+             * because we store all interval sets as enumerations of strings */
             if (var->info.valueQuantity == kokkos_value_set) {
                 std::list<std::string>& space = session.outputs[id]->space;
-                std::string& front = std::string(values[i].value.string_value);
-                auto tmp = request->add_param_enum(
-                    session.outputs[id]->name, front, space);
+                if (var->info.type == kokkos_value_double) {
+                    std::string front = std::to_string(values[i].value.double_value);
+                    auto tmp = request->add_param_enum(
+                        session.outputs[id]->name, front, space);
+                } else if (var->info.type == kokkos_value_int64) {
+                    std::string front = std::to_string(values[i].value.int_value);
+                    auto tmp = request->add_param_enum(
+                        session.outputs[id]->name, front, space);
+                } else if (var->info.type == kokkos_value_int64) {
+                    std::string front = std::string(values[i].value.string_value);
+                    auto tmp = request->add_param_enum(
+                        session.outputs[id]->name, front, space);
+                }
             } else {
                 if (var->info.type == kokkos_value_double) {
                     auto tmp = request->add_param_double(