Allow native process to load updatable driver.

Previously an application process can be specified to load the updatable
driver and the driver path will be set up correctly via
GraphicsEnvironment.java.  For a native process that is not an
application process, there's no way for it to be specificed to load the
updatable driver and hence the driver path is not set up. This patch
provides a way for a native process that runs in an environment, for
example shell, where environment variables can be set, to opt into using
udpatable driver by setting UPDATABLE_GFX_DRIVER to 1.

Bug: b/157832445, b/159240322
Test: ./gapit validate_gpu_profiling --os android
Change-Id: I597535caa5ae0a033c2b8d581bb39b14875ac8fc
Merged-In: I597535caa5ae0a033c2b8d581bb39b14875ac8fc