coverage: Migrate tests/run-coverage into tests/coverage

tests/coverage/nested_loops.rs

@@ -0,0 +1,25 @@
+fn main() {
+    let is_true = std::env::args().len() == 1;
+    let mut countdown = 10;
+
+    'outer: while countdown > 0 {
+        let mut a = 100;
+        let mut b = 100;
+        for _ in 0..50 {
+            if a < 30 {
+                break;
+            }
+            a -= 5;
+            b -= 5;
+            if b < 90 {
+                a -= 10;
+                if is_true {
+                    break 'outer;
+                } else {
+                    a -= 2;
+                }
+            }
+        }
+        countdown -= 1;
+    }
+}