[github-actions] add test to verify OTNS works (#4847)

script/check-simulation-build-autotools

@@ -107,6 +107,10 @@ build_all_features()
     export CPPFLAGS="${options[*]} -DOPENTHREAD_CONFIG_ASSERT_ENABLE=0"
     reset_source
     make -f examples/Makefile-simulation
+
+    export CPPFLAGS="${options[*]}"
+    reset_source
+    make -f examples/Makefile-simulation OTNS=1
 }
 
 build_nest_common()

script/check-simulation-build-cmake

@@ -78,6 +78,12 @@ build_all_features()
     cmake -GNinja "${options[@]}" ..
     ninja
     cd "$OT_SRCDIR"
+
+    reset_source
+    mkdir build && cd build
+    cmake -GNinja "${options[@]}" -DOT_OTNS=on -DOT_SIMULATION_VIRTUAL_TIME=on ..
+    ninja
+    cd ..
 }
 
 build_toranj()