chore(src/tests/util): fix gcc 6.2 warnings

src/tests/util/numerics/primes.cpp

@@ -31,8 +31,10 @@ static void tst2() {
     for (unsigned i = 0; i < 100000; i++) {
         uint64 p = it.next();
         lean_assert(is_prime(p));
-        if (i % 1000 == 0)
-            std::cout << p << " "; std::cout.flush();
+        if (i % 1000 == 0) {
+            std::cout << p << " ";
+            std::cout.flush();
+        }
     }
     std::cout << "\n";
 }

src/tests/util/sequence.cpp

@@ -25,7 +25,10 @@ static void tst1() {
     sequence<int> r = l4 + (l2 + l2) + (l3 + l4) + sequence<int>(3);
     buffer<int> b;
     r.linearize(b);
-    for (auto v : b) std::cout << v << " "; std::cout << "\n";
+    for (auto v : b) {
+      std::cout << v << " ";
+    }
+    std::cout << "\n";
     lean_assert(b[0] == 5 && b[1] == 10 && b[2] == 10 && b[3] == 20 && b[4] == 5 && b[5] == 3);
 }