Add temp arena support

tests/wapptest.cc

@@ -14,6 +14,8 @@ int main(void) {
 	wapp_tester_run_tests(
 		test_arena_allocator,
 		test_arena_allocator_with_buffer,
+		test_arena_allocator_temp_begin,
+		test_arena_allocator_temp_end,
 		test_arena_init_buffer,
 		test_arena_init_allocated,
 		test_arena_init_succeeds_when_reserving_very_large_size,
@@ -22,6 +24,8 @@ int main(void) {
 		test_arena_alloc_fails_when_over_capacity,
 		test_arena_realloc_bigger_size,
 		test_arena_realloc_smaller_size,
+		test_arena_temp_begin,
+		test_arena_temp_end,
 		test_arena_clear,
 		test_arena_destroy_buffer,
 		test_arena_destroy_allocated,