Make AsyncUnixTest/InterruptedTimer slower on Linux becaues it turns out to be…

Make AsyncUnixTest/InterruptedTimer slower on Linux becaues it turns out to be flaky on machines other than mine.

c++/src/kj/async-unix-test.c++

@@ -594,17 +594,16 @@ TEST(AsyncUnixTest, InterruptedTimer) {
   constexpr auto OS_SLOWNESS_FACTOR = 1;
 #else
   // OSX timeslices are 10ms, so we need longer timeouts to avoid flakiness.
-  // In fact, even 10x doesn't make OSX happy so we're pushing it to 100x.
   // To be safe we'll assume other OS's are similar.
-  constexpr auto OS_SLOWNESS_FACTOR = 100;
+  constexpr auto OS_SLOWNESS_FACTOR = 10;
 #endif
 
-  // Schedule a timer event in 10ms.
+  // Schedule a timer event in 100ms.
   auto& timer = port.getTimer();
   auto start = timer.now();
-  constexpr auto timeout = 10 * MILLISECONDS * OS_SLOWNESS_FACTOR;
+  constexpr auto timeout = 100 * MILLISECONDS * OS_SLOWNESS_FACTOR;
 
-  // Arrange SIGALRM to be delivered in 5ms, handled in an empty signal handler. This will cause
+  // Arrange SIGALRM to be delivered in 50ms, handled in an empty signal handler. This will cause
   // our wait to be interrupted with EINTR. We should nevertheless continue waiting for the right
   // amount of time.
   dummySignalHandlerCalled = false;
@@ -613,14 +612,14 @@ TEST(AsyncUnixTest, InterruptedTimer) {
   }
   struct itimerval itv;
   memset(&itv, 0, sizeof(itv));
-  itv.it_value.tv_usec = 5000 * OS_SLOWNESS_FACTOR;  // signal after 5ms
+  itv.it_value.tv_usec = 50000 * OS_SLOWNESS_FACTOR;  // signal after 50ms
   setitimer(ITIMER_REAL, &itv, nullptr);
 
   timer.afterDelay(timeout).wait(waitScope);
 
   KJ_EXPECT(dummySignalHandlerCalled);
   KJ_EXPECT(timer.now() - start >= timeout);
-  KJ_EXPECT(timer.now() - start <= timeout + (timeout / 5));  // allow 2ms error
+  KJ_EXPECT(timer.now() - start <= timeout + (timeout / 5));  // allow 20ms error
 }
 
 TEST(AsyncUnixTest, Wake) {