Use Arm optimised-routines for memory intrinsics.

Previously we were depending on Bionic's libc, which was pulling in a
bunch of other symbols we don't need or want.

Bug: 223166344
Test: atest vmbase_example.integration_test
Change-Id: I94c48d5b024f67a33c3ee9ad8d35b887c78c341f
diff --git a/vmbase/Android.bp b/vmbase/Android.bp
index 6400ccd..fb7f6a6 100644
--- a/vmbase/Android.bp
+++ b/vmbase/Android.bp
@@ -43,9 +43,9 @@
 cc_defaults {
     name: "vmbase_elf_defaults",
     defaults: ["vmbase_cc_defaults"],
-    system_shared_libs: ["libc"],
     static_executable: true,
     static_libs: [
+        "libarm-optimized-routines-mem",
         "libvmbase_entry",
     ],
 }