Add a stub for libicu.so

Bug: 160350521
Test: device boots
Change-Id: I0a77881c5fc3806c1d3bdb029b8ab3eba796ccbe
diff --git a/libicu/Android.bp b/libicu/Android.bp
index e48eaec..282b68d 100644
--- a/libicu/Android.bp
+++ b/libicu/Android.bp
@@ -43,6 +43,10 @@
     apex_available: [
         "com.android.i18n",
     ],
+    stubs: {
+        symbol_file: "libicu.map.txt",
+        versions: ["31"],
+    },
     target: {
         android: {
             version_script: "libicu.map.txt",