Build system_server jars with system_server api

modules_current is the correct API for bootclasspath module
libraries, but it is unnecessarily restrictive for system server jars.

Test: m
Change-Id: Ic84f4c5edb4444e4c3042e19cada0caca9b16e1d

sdk/Android.bp

@@ -126,16 +126,13 @@ java_defaults {
 
     // Collates API usages from each module for further analysis.
     plugins: ["java_api_finder"],
-
-    // Mainline modules should only rely on 'module_lib' APIs provided by other modules
-    // and the non updatable parts of the platform.
-    sdk_version: "module_current",
 }
 
 // Defaults for mainline module provided java_sdk_library instances.
 java_defaults {
     name: "framework-module-defaults",
     defaults: ["framework-module-common-defaults"],
+    sdk_version: "module_current",
 
     system: {
         enabled: true,
@@ -161,10 +158,11 @@ java_defaults {
 java_defaults {
     name: "framework-system-server-module-defaults",
     defaults: ["framework-module-common-defaults"],
+    sdk_version: "system_server_current",
 
     system_server: {
         enabled: true,
-        sdk_version: "module_current",
+        sdk_version: "system_server_current",
     },
     defaults_visibility: [
         ":__subpackages__",