Move the profile rule out of dex_preopt_libart.mk.

We only need to define it once. dex_preopt_libart.mk can be read
multiple times if there are many boot image.

Test: m && no warning
Bug:119800099

(cherry picked from commit 7e8ca9a1)

Change-Id: I16d67b77142fce93c6d4acc15f557ad073b2de44
Merged-In: If5b8fbb0c3310eb42f676d7b5267dcee679f7e19