Delay start of surfaceflinger until after the Runtime APEX is mounted.

It depends on libdexfile_external which is provided by the Runtime APEX.

Test: flash and boot
Test: atest CtsJdwpTestCases
Bug: 113373927
Change-Id: Ic3af21d74854cce02180d3d2e9e3b1b338456e46
Exempt-From-Owner-Approval: Trying this CL out for gathering numbers - will revert if substantial.
diff --git a/services/surfaceflinger/surfaceflinger.rc b/services/surfaceflinger/surfaceflinger.rc
index aea602b..5bec502 100644
--- a/services/surfaceflinger/surfaceflinger.rc
+++ b/services/surfaceflinger/surfaceflinger.rc
@@ -2,6 +2,7 @@
     class core animation
     user system
     group graphics drmrpc readproc
+    updatable
     onrestart restart zygote
     writepid /dev/stune/foreground/tasks
     socket pdx/system/vr/display/client     stream 0666 system graphics u:object_r:pdx_display_client_endpoint_socket:s0