feat: add new tests for loops

tests/programs/neg_infinite_for.fzs

@@ -0,0 +1,3 @@
+for (int i = 0; i < 5; i = i - 1)
+{}
+

tests/programs/neg_infinite_while.fzs

@@ -0,0 +1,3 @@
+while (true)
+{}
+

tests/programs/pos_loop_with_break.fzs

@@ -0,0 +1,7 @@
+int i = 0;
+
+for (;;)
+{
+  break;
+}
+

tests/programs/pos_loops.fzs

@@ -0,0 +1,27 @@
+for (int i = 0; i < 10; i = i + 1)
+  printline("check");
+
+int i = 0;
+for (i = 0; i <= 5; i = i + 1)
+{
+  printline("i is:");
+  printline(i);
+}
+
+if (i < 5)
+{
+  printline("external declared `i` != 5");
+  exit(1);
+}
+
+while (i > 0)
+{
+  i = i - 1;
+}
+
+if (i > 0)
+{
+  printline("decreased in while loop `i` > 0");
+  exit(1);
+}
+