Restructure and correct sleep utility for testing

test/src/sleep.c

@@ -0,0 +1,27 @@
+#include "test/jemalloc_test.h"
+
+/*
+ * Sleep for approximately ns nanoseconds.  No lower *nor* upper bound on sleep
+ * time is guaranteed.
+ */
+void
+sleep_ns(unsigned ns) {
+	assert(ns <= 1000*1000*1000);
+
+#ifdef _WIN32
+	Sleep(ns / 1000 / 1000);
+#else
+	{
+		struct timespec timeout;
+
+		if (ns < 1000*1000*1000) {
+			timeout.tv_sec = 0;
+			timeout.tv_nsec = ns;
+		} else {
+			timeout.tv_sec = 1;
+			timeout.tv_nsec = 0;
+		}
+		nanosleep(&timeout, NULL);
+	}
+#endif
+}