Update the reference profile from .dm files only during installs

In order to speed up first boot time we only create the current profile
and do not update the content of the reference profile. A system image
should already be configured with the right profile keys and the
profiles for the speed-profile prebuilds should already be copied (that's
done in #performDexOptUpgrade).

Test: manual (install apps and splits, take OTA)
Bug: 114046578

(cherry picked from commit 5c9a0085)

Merged-In: I99db76684430b929c52634c25b457e874648e205
Change-Id: I99db76684430b929c52634c25b457e874648e205