Label /system_ext/lib(64)/* as system_lib_file

This needs to be updated to api 30.0 which introduced the system_ext.

Bug: 160314910
Test: build and boot
Change-Id: I08c4aed640467d11482df08613039726e7395be0
diff --git a/prebuilts/api/30.0/private/file_contexts b/prebuilts/api/30.0/private/file_contexts
index 4b0cab7..9620b75 100644
--- a/prebuilts/api/30.0/private/file_contexts
+++ b/prebuilts/api/30.0/private/file_contexts
@@ -453,6 +453,8 @@
 /(system_ext|system/system_ext)/bin/aidl_lazy_test_server   u:object_r:aidl_lazy_test_server_exec:s0
 /(system_ext|system/system_ext)/bin/hidl_lazy_test_server   u:object_r:hidl_lazy_test_server_exec:s0
 
+/(system_ext|system/system_ext)/lib(64)?(/.*)?      u:object_r:system_lib_file:s0
+
 #############################
 # Vendor files from /(product|system/product)/vendor_overlay
 #
diff --git a/private/file_contexts b/private/file_contexts
index c477c67..9295769 100644
--- a/private/file_contexts
+++ b/private/file_contexts
@@ -456,6 +456,8 @@
 /(system_ext|system/system_ext)/bin/aidl_lazy_test_server   u:object_r:aidl_lazy_test_server_exec:s0
 /(system_ext|system/system_ext)/bin/hidl_lazy_test_server   u:object_r:hidl_lazy_test_server_exec:s0
 
+/(system_ext|system/system_ext)/lib(64)?(/.*)?      u:object_r:system_lib_file:s0
+
 #############################
 # Vendor files from /(product|system/product)/vendor_overlay
 #