Reland "EGL: Refactor multifile blobcache"

This reverts commit b81edf95

Previous revert was due to selinux denials causing test failures.
Temporarily addressed in aosp/2420100

This also incorporates additional post-submit feedback on ag/21091488

Test: pubg_mobile_launch ANGLE trace
Test: /data/nativetest64/EGL_test/EGL_test
Test: /data/nativetest64/libEGL_test/libEGL_test
Bug: b/266725576
Change-Id: I5631301c69605f25cbca52ca8ef096294c2e1bcf