Reworked unit tests for machine and renamed test_programs directory

test/riscv_instructions/simple_arithmetics/unsigned_addition.c

@@ -0,0 +1,9 @@
+#include "userlib/syscall.h"
+#include "userlib/libnachos.h"
+
+// EXPECTS TWO VARIABLES WITH A VALUE OF UNSIGNED 1
+int main() {
+    unsigned int x = 0;
+    unsigned int y = 1;
+    x = x + y;
+}