bootstrap-aws: Support aarch64.
bootstrap-aws: Support aarch64.

zulip/zulip,eeshangarg/zulip,rht/zulip,rht/zulip,kou/zulip,kou/zulip,eeshangarg/zulip,andersk/zulip,kou/zulip,zulip/zulip,kou/zulip,rht/zulip,andersk/zulip,kou/zulip,eeshangarg/zulip,zulip/zulip,andersk/zulip,kou/zulip,zulip/zulip,zulip/zulip,eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,kou/zulip,rht/zulip,rht/zulip,andersk/zulip,andersk/zulip,eeshangarg/zulip,andersk/zulip,rht/zulip,rht/zulip,andersk/zulip,zulip/zulip,eeshangarg/zulip