Update gold to a70724f.

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

Bug: http://b/21502954
Change-Id: I46081954236551d7194ea2550e1208f2d96df79d
diff --git a/bin/arm-linux-androideabi-ld.gold b/bin/arm-linux-androideabi-ld.gold
index 8b7c337..2df2f85 100755
--- a/bin/arm-linux-androideabi-ld.gold
+++ b/bin/arm-linux-androideabi-ld.gold
Binary files differ