Add support for instruction set features

This adds the --instruction-set-features= arguments to the dex2oat
commands for the system images.  The feature set is determined at
build time

(cherry picked from commit 4145a2a20a0f275fe4c77e39d507cd5f8eb7a73b)

Change-Id: I7f1ab44a561e24ad21ff8abe9b7636e04f833e0e