sleep/usleep: switch to trivial implementations.

Upstream keeps rearranging the deckchairs for these, so let's just
switch to the [roughly] one-liners rather than track that...

Test: treehugger
Change-Id: If655cf7a7f316657de44d41fadd43a8c55ee6f23
diff --git a/tests/utils.h b/tests/utils.h
index fe41019..1f4cece 100644
--- a/tests/utils.h
+++ b/tests/utils.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef __TEST_UTILS_H
-#define __TEST_UTILS_H
+#pragma once
 
 #include <dlfcn.h>
 #include <fcntl.h>
@@ -254,5 +253,3 @@
   std::string output_;
 };
 #endif
-
-#endif