Retrieve String/Class references from .data.bimg.rel.ro.

For PIC AOT-compiled app, use the .data.bimg.rel.ro to load
the boot image String/Class references instead of using the
mmapped boot image ClassTable and InternTable.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing --pictest --npictest
Test: Pixel 2 XL boots.
Test: testrunner.py --target --optimizing --pictest --npictest
Bug: 71526895
Change-Id: Id5703229777aecb589a933a41f92e44d3ec02a3d