base_system.mk: Support system_server jars from apexes

Allow system_server jars delivered via apex. Regular system_server
jars are located in /system/framework folder. But, jars delivered via
apex are mounted at /apex/<module_name>/javalib. Also, not all the
libraries in /apex/<module_name>/javalib will be a system_server jar,
so adding a mechanism to list out the jar file explicitly within the
apex module.

Bug: 144722612
Bug: 141785760
Test: Compiles (both with empty & non-empty PRODUCT_SYSTEM_SERVER_APEX_JARS
value set)

Change-Id: Ia181ab22fdf2da575bfd532c1cd90a2f54742528
diff --git a/core/dex_preopt_config.mk b/core/dex_preopt_config.mk
index 64ad8d9..c6c6a61 100644
--- a/core/dex_preopt_config.mk
+++ b/core/dex_preopt_config.mk
@@ -97,6 +97,7 @@
   $(call add_json_list, ProductUpdatableBootLocations,      $(PRODUCT_UPDATABLE_BOOT_LOCATIONS))
   $(call add_json_list, SystemServerJars,                   $(PRODUCT_SYSTEM_SERVER_JARS))
   $(call add_json_list, SystemServerApps,                   $(PRODUCT_SYSTEM_SERVER_APPS))
+  $(call add_json_list, UpdatableSystemServerJars,          $(PRODUCT_UPDATABLE_SYSTEM_SERVER_JARS))
   $(call add_json_list, SpeedApps,                          $(PRODUCT_DEXPREOPT_SPEED_APPS))
   $(call add_json_list, PreoptFlags,                        $(PRODUCT_DEX_PREOPT_DEFAULT_FLAGS))
   $(call add_json_str,  DefaultCompilerFilter,              $(PRODUCT_DEX_PREOPT_DEFAULT_COMPILER_FILTER))