Nest all namespaces

The compiler supports this now.  We can type less going forward.
No functional changes.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I29d6fa4f9aacc0e381f1a7637294db0392466995
diff --git a/aos/ipc_lib/lockless_queue_test.cc b/aos/ipc_lib/lockless_queue_test.cc
index 5b57aa9..bfd9916 100644
--- a/aos/ipc_lib/lockless_queue_test.cc
+++ b/aos/ipc_lib/lockless_queue_test.cc
@@ -39,9 +39,7 @@
 #endif
              "Number of threads to race");
 
-namespace aos {
-namespace ipc_lib {
-namespace testing {
+namespace aos::ipc_lib::testing {
 
 namespace chrono = ::std::chrono;
 
@@ -566,6 +564,4 @@
 
 #endif
 
-}  // namespace testing
-}  // namespace ipc_lib
-}  // namespace aos
+}  // namespace aos::ipc_lib::testing