[GL Loader] Extract loader logic to separate function calls.

We want to clean up our loader logic and eventually use properties to control
which driver should be loaded. In this patch, we extract the logic of loading
emulation driver and api initialization out as first step.

BUG: 127353494
Test: Build, flash and boot.
Change-Id: I19ce422488188892dc65ef6fdf853ecd52530eea