ART: Remove experimental flags for plugins and agents

Remove experimental flags guarding plugins and agents.

Partial revert of commit 7233c7e752c0d26387d143ee74420e9cd1f09390.
Partial revert of commit 185d134a3b43ab7529053e965917e0fa74bceba4.

Bug: 31455788
Test: m test-art-host
Change-Id: I11a19f24b88ced8da7a28e2cb7a2f602aab884a8
diff --git a/test/909-attach-agent/run b/test/909-attach-agent/run
index 985341b..0664592 100755
--- a/test/909-attach-agent/run
+++ b/test/909-attach-agent/run
@@ -21,17 +21,11 @@
   plugin=libopenjdkjvmti.so
 fi
 
-./default-run "$@" --experimental agents \
-                   --experimental runtime-plugins \
-                   --android-runtime-option -Xplugin:${plugin} \
+./default-run "$@" --android-runtime-option -Xplugin:${plugin} \
                    --android-runtime-option -Xfully-deoptable \
                    --args agent:${agent}=909-attach-agent
 
-./default-run "$@" --experimental agents \
-                   --experimental runtime-plugins \
-                   --android-runtime-option -Xfully-deoptable \
+./default-run "$@" --android-runtime-option -Xfully-deoptable \
                    --args agent:${agent}=909-attach-agent
 
-./default-run "$@" --experimental agents \
-                   --experimental runtime-plugins \
-                   --args agent:${agent}=909-attach-agent
+./default-run "$@" --args agent:${agent}=909-attach-agent