Don't modify -1 sensorHandle value

A -1 sensorHandle value is used to denote all active sensors should be
stopped for a given channel. Make sure the multi-HAL code doesn't modify
handles of this value or it'll corrupt them before passing to the direct
channel sub-HAL.

Bug: 153413565
Test: atest VtsHalSensorsV2_0Target
Change-Id: I3fe9cbf4661aa3db4ff534765d5112a193b7bf4a