Remove the 'optional' tag from demangle_fuzzer

This causes it to not actually be added to the tests zip, and it
is never available on-device unless *manually* built and pushed.

Test: mmma system/core/demangle
Change-Id: I7fd7f52726b9b981573063c32f25ccab933486a0
diff --git a/demangle/Android.mk b/demangle/Android.mk
index e3cfc2a..d8082a9 100644
--- a/demangle/Android.mk
+++ b/demangle/Android.mk
@@ -19,7 +19,6 @@
 include $(CLEAR_VARS)
 
 LOCAL_MODULE := demangle_fuzzer
-LOCAL_MODULE_TAGS := optional
 LOCAL_SRC_FILES := \
     Demangler.cpp \
     demangle_fuzzer.cpp \