Fix KalTrack.getIsoAndT0 sorting sensor's shared hit list in place

sensor.hits is shared by every track with a hit on that SiModule, and
ms.hitID indexes into it as populated at pattern recognition time.
Sorting it in place corrupted that ordering for every other track
sharing the sensor and made the subsequent ms.hitID lookup stale.
Sort a private copy instead and locate the hit on track by identity
in the sorted copy.

Also add Preselection2021.java, an LCSim driver for truth-based
electron/positron track and V0 preselection with per-layer isolation
diagnostics (including an exact iso==0 counter used to confirm the
residual zero-isolation entries in the innermost SiStriplet layers
are genuine, not an artifact of the sorting bug above).

Author: bloodyyugo