Add support for coverage flushing.

Register a callback to allow for coverage flushing on the HAL server.
The callback is tied to the property "hal.coverage.enable" and should
execute whenever the property has value "true".

Test: vts_sancov_configure
Bug: 64019182
Change-Id: I08f19ce84a1307dfb321ce2d46cafcf095643c5c
1 file changed