HIDL stuff on host.

The motivation of this is for quickly running unit tests of HAL
implementations on host. Before, you would have to abstract away
HIDL stuff, but now, you can just call a class that inherits from
HIDL stuff directly.

Currently, there is no binder or passthrough support on host though.
This is only for unit tests of C++ classes.

Bug: 124524556
Test: libhidl_test on host
Change-Id: I922060e48406ca196fbf864e549c05f5e1113d62
6 files changed