Reschedule the legacy bg dexopt job when it's cancelled.

We reschedule the new bg dexopt job when it's cancelled, so we should do
the same for the legacy bg dexopt job too to close the gap.

This change is essential to make the metrics comparison between two
implementations meaningful.

Bug: 263249979
Test: atest FrameworksMockingServicesTests:BackgroundDexOptServiceUnitTest
Change-Id: I33dfb84f3f3138df670ddfb5af72f017892d592b