Undo arm64 workaround.

Now we have new llvm to compile art for arm64 without -fno-vectorize.
BUG: 21080674

Change-Id: Id1b3a88ab9d4cf78b7f0dfd8cb435ed6e7ab7cb2
diff --git a/build/Android.common_build.mk b/build/Android.common_build.mk
index d1724cc..3e427a3 100644
--- a/build/Android.common_build.mk
+++ b/build/Android.common_build.mk
@@ -110,10 +110,6 @@
 ART_TARGET_CLANG_CFLAGS_arm64  += \
   -DNVALGRIND
 
-# FIXME: upstream LLVM has a vectorizer bug that needs to be fixed
-ART_TARGET_CLANG_CFLAGS_arm64 += \
-  -fno-vectorize
-
 # Warn about thread safety violations with clang.
 art_clang_cflags := -Wthread-safety