Move platform-private symbols out of libdl.so

Symbols not intended to be accessible from apps are moved to libdl_android.so

Test: bionic-unit-tests
Bug: http://b/129387775
Change-Id: Ib8ba6147a20cf56550c9a008f66570a2d419565a
(cherry picked from commit 2d6be9a751685b4c307632bf27e8c100310ad500)
diff --git a/libdl/libdl.map.txt b/libdl/libdl.map.txt
index 1514827..b4b4117 100644
--- a/libdl/libdl.map.txt
+++ b/libdl/libdl.map.txt
@@ -41,19 +41,7 @@
     __cfi_slowpath_diag;
 } LIBC_N;
 
-LIBC_Q { # introduced=29
-  global:
-    android_create_namespace; # apex
-    android_dlwarning; # apex
-    android_get_LD_LIBRARY_PATH; # apex
-    android_get_exported_namespace; # apex
-    android_init_anonymous_namespace; # apex
-    android_link_namespaces; # apex
-    android_set_application_target_sdk_version; # apex
-} LIBC_OMR1;
-
 LIBC_PLATFORM {
   global:
     __cfi_init;
-    android_update_LD_LIBRARY_PATH;
-} LIBC_Q;
+} LIBC_OMR1;