Update gold to a70724f.

Contains yiran's work around for the overly aggressive hidden symbol
warning.

Bug: http://b/21502954
Change-Id: I576ff3fb4b63fadf08d130c68ba35ae53b2e5bc9
diff --git a/bin/aarch64-linux-android-ld.gold b/bin/aarch64-linux-android-ld.gold
index dafcf47..6e44d28 100755
--- a/bin/aarch64-linux-android-ld.gold
+++ b/bin/aarch64-linux-android-ld.gold
Binary files differ