Defer to Legacy driver if ANGLE deferlist hasn't been initialized

ANGLE's deferlist is populated by the GUI code in the ANGLE APK.  This
code is not immediately run upon first-boot of a newly-flashed device.
This change puts a default deferlist into the GraphicsEnvironment
class, which will be used if the deferlist has not yet been processed.

Bug: 241757590
Test: Manually test and inspect logcat output
Change-Id: I12f355e891dfa466be37da5282af7a9586066c93