PerfTest driver: remove traits enumeration underlying bool type

This feature is not well supported by compilers. The traits values are
only used at comiple time.

Tests/noDist/PerfTest/TestDriver.hpp

@@ -30,10 +30,10 @@ namespace scalfmm  {
             /// Disabled type trait specialisation
             template<class U>
             struct disabled<U, void_t<decltype(U::disabled)> >
-            { enum : bool { value = U::disabled }; };
+            { enum { value = U::disabled }; };
 
             /// Type trait value, true if the T is enabled
-            enum : bool {value = !disabled<T>::value};
+            enum {value = !disabled<T>::value};
         };
 
         /**
@@ -150,20 +150,20 @@ namespace scalfmm  {
 
 
             /// Shorthand for the tree factory type trait value
-            enum : bool { has_tree_factory_v =
-                    has_tree_factory<tree_desc>::value };
+            enum { has_tree_factory_v =
+                   has_tree_factory<tree_desc>::value };
 
             /// Shorthand for the loader factory type trait value
-            enum : bool { has_loader_factory_v =
-                    has_loader_factory<algo_desc>::value };
+            enum { has_loader_factory_v =
+                   has_loader_factory<algo_desc>::value };
 
             /// Shorthand for the kernel factory type trait value
-            enum : bool { has_kernel_factory_v =
-                    has_kernel_factory<kernel_desc>::value };
+            enum { has_kernel_factory_v =
+                   has_kernel_factory<kernel_desc>::value };
 
             /// Shorthand for the algorithm factory type trait value
-            enum : bool { has_algo_factory_v =
-                    has_algo_factory<algo_desc>::value };
+            enum { has_algo_factory_v =
+                   has_algo_factory<algo_desc>::value };
 
 
             /**
@@ -224,7 +224,7 @@ namespace scalfmm  {
                     : std::true_type {};
 
                 /// Type trait value, true if the build expression is declared
-                enum : bool {value = valid_build_expression<algo_factory>::value};
+                enum {value = valid_build_expression<algo_factory>::value};
             };
 
             /**
@@ -236,10 +236,10 @@ namespace scalfmm  {
 
 
             /// Shorthand for the build compatibility type trait value
-            enum : bool { can_build_algo_v = can_build_algo<void>::value };
+            enum { can_build_algo_v = can_build_algo<void>::value };
 
             /// Type trait value, true if the algorithm & kernel seem compatible
-            enum : bool {
+            enum {
                 value = has_tree_factory_v
                     && has_loader_factory_v
                     && has_kernel_factory_v