unit tests: fix warnings, build with -Werror

- libsodium: silence warnings
- unit tests: fix warnings
- spiram: fix warnings
- ringbuf test: enable by default, reduce delays

tools/unit-test-app/components/unity/unity_platform.c

@@ -10,9 +10,12 @@
 #include "esp_log.h"
 #include "soc/cpu.h"
 #include "esp_heap_caps.h"
-#include "esp_heap_trace.h"
 #include "test_utils.h"
 
+#ifdef CONFIG_HEAP_TRACING
+#include "esp_heap_trace.h"
+#endif
+
 #define unity_printf ets_printf
 
 // Pointers to the head and tail of linked list of test description structs: