Fix bionic-unit-tests-glibc-run target

Configure multilib for bionic-unit-tests-glibc-run target (the path to
the host executable was already patched to support multilib build but
the multilib itself wasn't configured).

Change-Id: If533fbdb19bc737e543cf85a0787505458f24579
diff --git a/tests/Android.mk b/tests/Android.mk
index fccf3f1..bd77c9e 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -271,6 +271,7 @@
 
 module := bionic-unit-tests-glibc
 module_tag := optional
+bionic-unit-tests-glibc_multilib := both
 build_type := host
 build_target := NATIVE_TEST
 include $(LOCAL_PATH)/Android.build.mk