Take libcore off the LP64 blacklist.

Change-Id: I34bc49370ecdd37f83927c3829c775e404bcbd73
diff --git a/core/64_bit_blacklist.mk b/core/64_bit_blacklist.mk
index 71a5cf3..99db95d 100644
--- a/core/64_bit_blacklist.mk
+++ b/core/64_bit_blacklist.mk
@@ -5,7 +5,6 @@
 	external/conscrypt \
 	external/neven \
 	external/svox \
-	libcore \
 	packages \
 
 # Chromium/V8: needs 64-bit support