Rollback during bootloop

In V as part of improvements to Rescue Party we added a mitigation to
try rolling back GMS core in response to bootloop. But during testing we
realized that RollbackPackageHealthObserver isnt even initialized when
noteBoot is called. On further testing we found out that none of the
existing mitigations were actually working for Rescue party where
noteBoot is currently called. So we decided to move RescueParty
initialization to much later in the boot process so that, if
system_server doesnt crash till then, Rescue party would get an
opportunity to apply mitigations.

When we tried rollback during boot, package varification would fail
because its too early in the initialization for it to work. Since
rollback wouldnt really need a package verification, we have disabled
package verification for rollback scenario. After this was fixed, found
that dexOpt was taking too long and watchdog would kill the thread that
was installing GMS core. To get through installation in emergency
scenarios disabled dexOpt for rollbacks.

Test: manual
Bug: 291137901
Change-Id: Ic46643525e28db9470a7ba0139cfba8526b4842d