CONTRIBUTORS: add contributors

Add contributors authored CLs in the past.

Change-Id: I029c5e872df72a90d9a95c320476909bd6f392ef
Reviewed-on: https://go-review.googlesource.com/c/gollvm/+/317892
Trust: Cherry Mui <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>

CONTRIBUTORS

diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 13b44ee..f5b288b 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -26,7 +26,11 @@
 
 # Please keep the list sorted.
 
+Aaqa Ishtyaq <aaqaishtyaq@gmail.com>
 Cherry Mui <cherryyz@google.com>
+Eric Fang <eric.fang@arm.com>
 Ian Lance Taylor <iant@golang.org>
+Ivan Serdyuk <local.tourist.kiev@gmail.com>
 Than McIntosh <thanm@google.com>
-
+Ting Yuan <yuanting@ict.ac.cn>
+Xiangdong Ji <xiangdong.ji@arm.com>