[GL Loader] Split loading logic based on API set and driver choices.

Previously, the order of loading the graphics driver is:
1) Try to load libGLES from ANGLE -> Driver apk -> emulation driver -> system;
2) If 1) fails, fall back to load [libEGL, libGLESv1_CM, libGLESv2] from ANGLE
  -> Driver apk -> emulation driver -> system.

However, there might be multiple variants of the same library exist in the
device and they all follow the same naming convention, which makes the driver
loading choice unpredictable. This patch refactors this ordering such that, we
loop over driver choices first, and for each driver choice, we try to see if we
can load either libGLES or [libEGL, libGLESv1_CM, libGLESv2] from it, if fails,
proceed to the next driver choice.

Minor: Code clean up here and there.

BUG: 127353494
Test: Build, verified with Developer Options and emulator
Test: atest CtsAngleIntegrationHostTestCases
Change-Id: I408dc20d8e41f69eac25c943e7c79af559d3d160