Put a pile of code into the concurrent_signals tight loop so it repla…

…ys faster with large skid values

src/test/concurrent_signals.c

@@ -8,14 +8,39 @@ static void handler(__attribute__((unused)) int sig) {}
 
 static void term_handler(__attribute__((unused)) int sig) { stop = 1; }
 
+#define STATEMENT(i)                                                           \
+  if (a * (i) < b) {                                                           \
+    ++a;                                                                       \
+  } else {                                                                     \
+    ++b;                                                                       \
+  }
+#define STATEMENT2(i) STATEMENT(i) STATEMENT(i + 1)
+#define STATEMENT4(i) STATEMENT2(i) STATEMENT2(i + 2)
+#define STATEMENT8(i) STATEMENT4(i) STATEMENT4(i + 4)
+#define STATEMENT16(i) STATEMENT8(i) STATEMENT8(i + 8)
+#define STATEMENT32(i) STATEMENT16(i) STATEMENT16(i + 16)
+#define STATEMENT64(i) STATEMENT32(i) STATEMENT32(i + 32)
+#define STATEMENT128(i) STATEMENT64(i) STATEMENT64(i + 64)
+#define STATEMENT256(i) STATEMENT128(i) STATEMENT128(i + 128)
+#define STATEMENT512(i) STATEMENT256(i) STATEMENT256(i + 256)
+#define STATEMENT1024(i) STATEMENT512(i) STATEMENT512(i + 512)
+#define STATEMENT2048(i) STATEMENT1024(i) STATEMENT1024(i + 1024)
+#define STATEMENT4096(i) STATEMENT2048(i) STATEMENT2048(i + 2048)
+
+static volatile int a;
+static volatile int b;
+static volatile int i;
+
 int main(void) {
   test_assert(0 == signal(SIGUSR1, handler));
   test_assert(0 == signal(SIGUSR2, handler));
   test_assert(0 == signal(SIGTERM, term_handler));
 
   atomic_puts("ready");
 
-  while (!stop) {}
+  while (!stop) {
+    STATEMENT4096(i);
+  }
 
   atomic_puts("EXIT-SUCCESS");
   return 0;