Faster `HLoadClass` for app image classes.

Add app image relocations for classes in the app image,
similar to the existing relocations for boot image. This new
load kind lets the compiled code avoid the null check and
slow path.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing --speed-profile
Test: run-test.sh
Test: testrunner.py --target --optimizing --speed-profile
Bug: 38313278
Change-Id: Iffd76fe9ac6b95c37c2781fd6257e1d5cd0790d0
31 files changed