ANGLE: Allow libs from debug package

Add a new setting that allows a developer to specify where
to load ANGLE libraries from, rather than the default location.
This is only allowed for apps that are dumpable, i.e. can have
libraries injected.  That includes debuggable, profileable,
and root.

To use the new setting:

  adb shell settings put global angle_debug_package <package>

This allows a developer to build an APK directly from Chromium
and use it with a production build of Android. It will override
pre-installed system packages and updates.

Note: Use of ANGLE Developer Options UI will cease to function
until the debug package is uninstalled.

Bug: 80239516
Test: Apply setting, see new ANGLE used
Test: cts-tradefed run singleCommand cts -m CtsAngleIntegrationHostTestCases

Change-Id: Ib3b1fb52c0eb669e7ea931959a73aba2bd15bedf