[test] Re-enable aarch64build test

This test was disabled in PR facebook#2783 due to triggering an ICE. Re-enable
the test now that it doesn't trigger the same ICE.

Fixes facebook#2785.

Author: terrelln

.circleci/config.yml

@@ -7,8 +7,8 @@ jobs:
     #       preinstalled to reduce installation time.
     docker:
       - image: fbopensource/zstd-circleci-primary:0.0.1
-    # TODO: Re-enable aarch64 build:
-    #       make aarch64build     && make clean
+    TODO: Re-enable aarch64 build:
+          make aarch64build     && make clean
     steps:
       - checkout
       - run: