tests/playback: due to popular demand mv them from examples to icles

The tests are toys and not reference demos.
diff --git a/configure.ac b/configure.ac
index 2cc5cf1..0b58d2b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -953,13 +953,13 @@
 tests/examples/dynamic/Makefile
 tests/examples/gio/Makefile
 tests/examples/overlay/Makefile
-tests/examples/playback/Makefile
 tests/examples/seek/Makefile
 tests/examples/snapshot/Makefile
 tests/examples/volume/Makefile
 tests/examples/v4l/Makefile
 tests/files/Makefile
 tests/icles/Makefile
+tests/icles/playback/Makefile
 docs/Makefile
 docs/design/Makefile
 docs/libs/Makefile